Found 25 papers in cond-mat
Date of feed: Wed, 14 Jun 2023 00:30:00 GMT

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Strongly-Correlated Electron-Photon Systems. (arXiv:2306.07313v1 [cond-mat.str-el])
Jacqueline Bloch, Andrea Cavalleri, Victor Galitski, Mohammad Hafezi, Angel Rubio

An important goal of modern condensed matter physics involves the search for states of matter with new emergent properties and desirable functionalities. Although the tools for material design remain relatively limited, notable advances have been recently achieved by controlling interactions at hetero-interfaces, precise alignment of low-dimensional materials and the use of extreme pressures . Here, we highlight a new paradigm, based on controlling light-matter interactions, which provides a new way to manipulate and synthesize strongly correlated quantum matter. We consider the case in which both electron-electron and electron-photon interactions are strong and give rise to a variety of novel phenomena. Photon-mediated superconductivity, cavity-fractional quantum Hall physics and optically driven topological phenomena in low dimensions are amongst the frontiers discussed in this perspective, which puts a spotlight on a new field that we term here "strongly-correlated electron-photon science."


Monopoles, Scattering, and Generalized Symmetries. (arXiv:2306.07318v1 [hep-th])
Marieke van Beest, Philip Boyle Smith, Diego Delmastro, Zohar Komargodski, David Tong

We reconsider the problem of electrically charged, massless fermions scattering off magnetic monopoles. The interpretation of the outgoing states has long been a puzzle as, in certain circumstances, they necessarily carry fractional quantum numbers. We argue that consistency requires such outgoing particles to be attached to a topological co-dimension 1 surface, which ends on the monopole. This surface cannot participate in a 2-group with the magnetic 1-form symmetry and is often non-invertible. Equivalently, the outgoing radiation lies in a twisted sector and not in the original Fock space. The outgoing radiation therefore not only carries unconventional flavor quantum numbers, but is often trailed by a topological field theory. We exemplify these ideas in the 1+1 dimensional, chiral 3450 model which shares many of the same features.

We comment on the effects of gauge field fluctuations on the lowest angular momentum fermion scattering states in the presence of a magnetic monopole. While, to leading order, these zero modes can penetrate into the monopole core, in the full theory some of the zero modes are lifted and develop a small centrifugal barrier. The dynamics of the zero modes is that of a multi-flavor Schwinger model with a space-dependent gauge coupling. Symmetries and anomalies constrain the fate of the pseudo-zero modes.


Quantum geometry of singlet superconductors. (arXiv:2306.07366v1 [cond-mat.supr-con])
David Porlles, Wei Chen

We elaborate that $s$-wave and $d$-wave superconductors described by mean field theories possess a nontrivial quantum geometry. From the overlap of two quasihole states at slightly different momenta, one can define a quantum metric that measures the distance in the curved momentum space. The momentum-integration of the quantum metric represents an average distance that we call the fidelity number, which may be further expressed as a fidelity marker defined locally on every lattice site. For $s$-wave superconductors, we unveil that the quantum metric generally influences the electromagnetic responses at finite wave length, such as the infrared absorption and paramagnetic current. In addition, the dielectric response is directly proportional to the fidelity number, which is found to be determined by the coherence length and suppressed by disorder. For $d$-wave superconductors, we demonstrate the singular behavior of the quantum metric near the nodal points, and a metric-curvature correspondence between the azimuthal quantum metric and the non-Abelian Berry connection that integrates to a topological charge of the nodal points.


Nanomechanical behavior of pentagraphyne-based single-layer and nanotubes through reactive classical molecular dynamics. (arXiv:2306.07370v1 [physics.comp-ph])
J. M. De Sousa, W. H. S. Brandão, W. L. A. P. Silva, L. A. Ribeiro Junior, D. S. Galvão, M. L. Pereira Júnior

In a recent theoretical study, a new 2D carbon allotrope called pentagraphyne (PG-yne) was proposed. This allotrope is derived from pentagraphene by introducing acetylenic linkages between sp3 and sp2 hybridized carbon atoms. Due to its interesting electronic and structural properties, it is of interest to investigate the mechanical behavior of PG-yne in both monolayer and nanotube topologies. To achieve this, we performed fully atomistic reactive (ReaxFF) molecular dynamics simulations, and our results show that Young's modulus average of PG-yne monolayers is approximately 913 GPa, at room temperature. In comparison, it ranges from 497-789 GPa for the nanotubes studied. Furthermore, we observed that PG-yne monolayers exhibit a direct transition from elastic to complete fracture under critical strain without a plastic regime. In contrast, some PG-yne nanotubes exhibit an extended flat plastic regime before total fracture.


High-temperature Majorana corner modes in a $d+id'$ superconductor heterostructure: Application to twisted bilayer cuprate superconductors. (arXiv:2306.07468v1 [cond-mat.supr-con])
Yu-Xuan Li, Cheng-Cheng Liu

The realization of Majorana corner modes generally requires unconventional superconducting pairing or $s$-wave pairing. However, the bulk nodes in unconventional superconductors and the low $T_c$ of $s$-wave superconductors are not conducive to the experimental observation of Majorana corner modes. Here we show the emergence of a Majorana corner mode at each corner of a two-dimensional topological insulator in proximity to a $d+id'$ pairing superconductor, such as heavily doped graphene or especially a twisted bilayer of a cuprate superconductor, e.g., Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$, which has recently been proposed as a fully gapped chiral $d_{x^2-y^2}+id_{xy}$ superconductor with $T_c$ close to its native 90 K, and an in-plane magnetic field. By numerical calculation and intuitive edge theory, we find that the interplay of the proximity-induced pairing and Zeeman field can introduce opposite Dirac masses on adjacent edges of the topological insulator, which creates one zero-energy Majorana mode at each corner. Our scheme offers a feasible route to achieve and explore Majorana corner modes in a high-temperature platform without bulk superconductor nodes.


Backscattering-free edge states below all bands in two-dimensional auxetic media. (arXiv:2306.07493v1 [cond-mat.soft])
Wenting Cheng, Kai Qian, Nan Cheng, Nicholas Boechler, Xiaoming Mao, Kai Sun

Unidirectional and backscattering-free propagation of sound waves is of fundamental interest in physics, and highly sought-after in engineering. Current strategies utilize topologically protected chiral edge modes in bandgaps, or complex mechanisms involving active constituents or nonlinearity. Here we propose a new class of passive, linear, one-way edge states based on spin-momentum locking of Rayleigh waves in two-dimensional media in the limit of vanishing bulk modulus, which provides $100\%$ unidirectional and backscattering-free edge propagation at a broad range of frequencies instead of residing in gaps between bulk bands. We further show that such modes are characterized by a new topological winding number that is analogous to discrete angular momentum eigenvalues in quantum mechanics. These passive and backscattering-free edge waves have the potential to enable a new class of phononic devices in the form of lattices or continua that work in previously inaccessible frequency ranges.


Graphene-Enhanced Single Ion Detectors for Deterministic Near-Surface Dopant Implantation in Diamond. (arXiv:2306.07496v1 [cond-mat.mes-hall])
Nicholas F. L. Collins, Alexander M. Jakob, Simon G. Robson, Shao Qi Lim, Paul Räcke, Brett C. Johnson, Boqing Lui, Yurei Lu, Daniel Spemann, Jeffrey C. McCallum, David N. Jamieson

Colour centre ensembles in diamond have been the subject of intensive investigation for many applications including single photon sources for quantum communication, quantum computation with optical inputs and outputs, and magnetic field sensing down to the nanoscale. Some of these applications are realised with a single centre or randomly distributed ensembles in chips, but the most demanding application for a large-scale quantum computer will require ordered arrays. By configuring an electronic-grade diamond substrate with a biased surface graphene electrode connected to charge-sensitive electronics, it is possible to demonstrate deterministic single ion implantation for ions stopping between 30 and 130~nm deep from a typical stochastic ion source. An implantation event is signalled by a charge pulse induced by the drift of electron-hole pairs from the ion implantation. The ion implantation site is localised with an AFM nanostencil or a focused ion beam. This allows the construction of ordered arrays of single atoms with associated colour centres that paves the way for the fabrication of deterministic colour center networks in a monolithic device.


Atomically precise incorporation of BN doped rubicene into graphene nanoribbons. (arXiv:2306.07586v1 [cond-mat.mtrl-sci])
Remy Pawlak, Khalid N. Anindya, Toshiki Shimizu, Jung-Ching Liu, Takumi Sakamaki, Rui Shang, Alain Rochefort, Eiichi Nakamura, Ernst Meyer

Substituting heteroatoms and non-benzenoid carbons into nanographene structure offers an unique opportunity for atomic engineering of electronic properties. Here we show the bottom-up synthesis of graphene nanoribbons (GNRs) with embedded fused BN-doped rubicene components on a Au(111) surface using on-surface chemistry. Structural and electronic properties of the BN-GNRs are characterized by scanning tunneling microscopy (STM) and atomic force microscopy (AFM) with CO-terminated tips supported by numerical calculations. The periodic incorporation of BN heteroatoms in the GNR leads to an increase of the electronic band gap as compared to its undoped counterpart. This opens avenues for the rational design of semiconducting GNRs with optoelectronic properties.


Reduced energies for thin ferromagnetic films with perpendicular anisotropy. (arXiv:2306.07634v1 [math.AP])
G. Di Fratta, C. B. Muratov, V. V. Slastikov

We derive four reduced two-dimensional models that describe, at

different spatial scales, the micromagnetics of ultrathin

ferromagnetic materials of finite spatial extent featuring

perpendicular magnetic anisotropy and interfacial

Dzyaloshinskii-Moriya interaction. Starting with a microscopic model

that regularizes the stray field near the material's lateral edges,

we carry out an asymptotic analysis of the energy by means of

$\Gamma$-convergence. Depending on the scaling assumptions on the

size of the material domain vs. the strength of dipolar interaction,

we obtain a hierarchy of the limit energies that exhibit

progressively stronger stray field effects of the material

edges. These limit energies feature, respectively, a renormalization

of the out-of-plane anisotropy, an additional local boundary penalty

term forcing out-of-plane alignment of the magnetization at the

edge, a pinned magnetization at the edge, and, finally, a pinned

magnetization and an additional field-like term that blows up at the

edge, as the sample's lateral size is increased. The pinning of the

magnetization at the edge restores the topological protection and

enables the existence of magnetic skyrmions in bounded samples.


Crossed Andreev reflection and elastic co-tunneling in a three-site Kitaev chain nanowire device. (arXiv:2306.07696v1 [cond-mat.mes-hall])
Alberto Bordin, Xiang Li, David van Driel, Jan Cornelis Wolff, Qingzhen Wang, Sebastiaan L. D. ten Haaf, Guanzhong Wang, Nick van Loo, Leo P. Kouwenhoven, Tom Dvir

The formation of a topological superconducting phase in a quantum-dot-based Kitaev chain requires nearest neighbor crossed Andreev reflection and elastic co-tunneling. Here we report on a hybrid InSb nanowire in a three-site Kitaev chain geometry - the smallest system with well-defined bulk and edge - where two superconductor-semiconductor hybrids separate three quantum dots. We demonstrate pairwise crossed Andreev reflection and elastic co-tunneling between both pairs of neighboring dots and show sequential tunneling processes involving all three quantum dots. These results are the next step towards the realization of topological superconductivity in long Kitaev chain devices with many coupled quantum dots.


Towards a better understanding of granular flows. (arXiv:2306.07717v1 [cond-mat.stat-mech])
Vicente Garzó

Understanding the transport of particles immersed in a carrier fluid (bedload transport) is still an exciting challenge. Among the different types of gas-solid flows, when the dynamics of solid particles is essentially dominated by collisions between them, kinetic theory can be considered as a reliable tool to derive continuum approaches from a fundamental point of view. In a recent paper, Chassagne et al. [J. Fluid Mech. 964, A27, (2023)] have proposed a two-fluid model based on modifications to a classical kinetic theory model. First, in contrast to the classical model, the model proposed by Chassagne et al. (2023) takes into account the interparticle friction not only in the radial distribution function but also through an effective restitution coefficient in the rate of dissipation term of granular temperature. As a second modification, at the top of the bed where the volume fraction is quite small, the model accounts for the saltation regime in the continuum framework. The theoretical results derived from the model agree with discrete simulations for moderate and high densities and they are also consistent with experiments. Thus, the model proposed by Chassagne et al. (2023) helps to a better understanding on the combined impact of friction and inelasticity on the macroscopic properties of granular flows.


The Haldane Model with Chiral Edge States using a Synthetic Dimension. (arXiv:2306.07752v1 [cond-mat.quant-gas])
Joel Priestley, Gerard Valentí-Rojas, Patrik Öhberg

We explicitly show that the differences, with respect to the appearance of topological phases, between the traditional Haldane model, which utilises a honeycomb lattice structure, to that of the Haldane model imbued onto a brick-wall lattice geometry, are inconsequential. A proposal is then put forward to realise the Haldane model by exploiting the internal degrees of freedom of atoms as a synthetic dimension. This leads to a convenient platform for the investigation of chiral edge states due to the hard boundaries provided by the hyperfine manifold. We make some cursory comments on the effects of interactions in the system.


Optical properties of two-dimensional tin nanosheets epitaxially grown on graphene. (arXiv:2306.07773v1 [cond-mat.mtrl-sci])
Eleonora Bonaventura, Christian Martella, Salvatore Macis, Daya S. Dhungana, Simonas Krotkus, Michael Heuken, Stefano Lupi, Alessandro Molle, Carlo Grazianetti

Heterostacks formed by combining two-dimensional materials show novel properties which are of great interest for new applications in electronics, photonics and even twistronics, the new emerging field born after the outstanding discoveries on twisted graphene. Here, we report the direct growth of tin nanosheets at the two-dimensional limit via molecular beam epitaxy on chemical vapor deposited graphene on Al2O3(0001). The mutual interaction between the tin nanosheets and graphene is evidenced by structural and chemical investigations. On the one hand, Raman spectroscopy indicates that graphene undergoes compressive strain after the tin growth, while no charge transfer is observed. On the other hand, chemical analysis shows that tin nanosheets interaction with sapphire is mediated by graphene avoiding the tin oxidation occurring in the direct growth on this substrate. Remarkably, optical measurements show that the absorption of tin nanosheets show a graphene-like behavior with a strong absorption in the ultraviolet photon energy range, therein resulting in a different optical response compared to tin nanosheets on bare sapphire. The optical properties of tin nanosheets therefore represent an open and flexible playground for the absorption of light in a broad range of the electromagnetic spectrum and technologically relevant applications for photon harvesting and sensors.


Non-coplanar Long Wavelength Magnetism and Charge Order in the Kagome-based Weyl Semimetal Mn$_{3}$Sn. (arXiv:2306.07822v1 [cond-mat.str-el])
Y. Chen, J. Gaudet, G. G. Marcus, T. Nomoto, T. Chen, T. Tomita, M. Ikhlas, Y. Zhao, W. C. Chen, J. Strempfer, R. Arita, S. Nakatsuji, C. Broholm

The magnetism of the kagome-based Weyl semi-metal \ce{Mn3Sn} is explored using neutron and X-ray scattering. A co-planar anti-chiral ${\textbf k}={\textbf 0}$ magnetic order develops below $T_{\mathrm{N}}$~=~445~K, with an ordered moment of 2.1(1)$\mu_{B}$/Mn and a correlation length exceeding 350~nm at $T=300$~K. For $T<T_{\rm inc}=285$~K, this structure is replaced by an incommensurate non-coplanar structure composed of a transverse polarized helimagnet with wave vector $\textbf{k}_{\chi}=k_\chi{\bf \hat{c}}$ and a longitudinally polarized spin density wave with $\textbf{k}_{\beta}=k_\beta {\bf \hat{c}}$. Very interestingly, charge density waves with wave vectors $2\textbf{k}_\beta, 2\textbf{k}_\chi$, and $\textbf{k}_\beta+\textbf{k}_\chi$ accompany the magnetic order. While $k_\beta(T)$ and $k_\chi(T)$ vary differently with temperature, their trajectories intersect and lock for 200 K$<T<240$~K. For $T<100$~K, $k_\beta=0.08446(1)c^*\approx \frac{1}{12}c^{*}$ while $k_\chi=0.1039(4)c^*\approx\frac{5}{48}c^{*}$ for $T<25$~K. The $\bf Q$-dependence of inelastic neutron scattering for $\hbar\omega <10$~meV reflects $k_\beta \approx k_\chi$ for all $T<300$~K. While a single $\Gamma-$point mode at $\Delta=4.5$~meV is observed in the commensurate phase, there are modes at $\Delta_{1}=5.0(5)~\mathrm{meV},\Delta_{2}=7.0(5)~\mathrm{meV}$, and $\Delta_{3}=8.5(5)~\mathrm{meV}$ in the lower symmetry modulated phase.


Electrostatic moir\'e potential from twisted-hBN layers. (arXiv:2306.07841v1 [cond-mat.mtrl-sci])
Dong Seob Kim, Roy C. Dominguez, Rigo Mayorga-Luna, Dingyi Ye, Jacob Embley, Tixuan Tan, Yue Ni, Zhida Liu, Mitchell Ford, Frank Y. Gao, Saba Arash, Kenji Watanabe, Takashi Taniguchi, Suenne Kim, Chih-Kang Shih, Keji Lai, Wang Yao, Li Yang, Xiaoqin Li, Yoichi Miyahara

Moir\'e superlattices formed by vertically stacking van der Waals layers host a rich variety of correlated electronic phases and function as novel photonic materials. The moir\'e potential of the superlattice, however, is fixed by the interlayer coupling of the stacked functional layers (e.g. graphene) and dependent on carrier types (e.g. electrons or holes) and valleys (e.g. {\Gamma} vs. K). In contrast, twisted hexagonal boron nitride (hBN) layers are predicted to impose a periodic electrostatic potential that may be used to engineer the properties of an adjacent functional thin layer. Here, we show that this potential is described by a simple theory of electric polarization originating from the interfacial charge redistribution, validated by its dependence on supercell sizes and distance from the twisted interfaces. We demonstrate that the potential depth and profile can be further controlled by assembling a double moir\'e structure. When the twist angles are similar at the two interfaces, the potential is deepened by adding the potential from the two twisted interfaces, reaching ~ 400 meV. When the twist angles are dissimilar at the two interfaces, multi-level polarization states are observed. As an example of controlling a functional layer, we demonstrate how the electrostatic potential from a twisted hBN substrate impedes exciton diffusion in a semiconductor monolayer. These findings suggest exciting opportunities for engineering properties of an adjacent functional layer using the surface potential of a twisted hBN substrate.


Tiny Sc allows the chains to rattle: Impact of Lu and Y doping on the charge density wave in ScV$_6$Sn$_6$. (arXiv:2306.07868v1 [cond-mat.str-el])
William R. Meier, Richa Pokharel Madhogaria, Shirin Mozaffari, Madalynn Marshall, David E. Graf, Michael A. McGuire, Hasitha W. Suriya Arachchige, Caleb L. Allen, Jeremy Driver, Huibo Cao, David Mandrus

The kagome metals display an intriguing variety of electronic and magnetic phases arising from the connectivity of atoms on a kagome lattice. A growing number of these materials with vanadium kagome nets host charge density waves (CDWs) at low temperatures including ScV$_6$Sn$_6$, CsV$_3$Sb$_5$, and V$_3$Sb$_2$. Curiously, only the Sc version of the $R$V$_6$Sn$_6$ HfFe$_6$Ge$_6$-type materials hosts a CDW ($R = $Gd-Lu, Y, Sc). In this study we investigate the role of rare earth size in CDW formation in the $R$V$_6$Sn$_6$ compounds. Magnetization measurements on our single crystals of (Sc,Lu)V$_6$Sn$_6$ and (Sc,Y)V$_6$Sn$_6$ establish that the CDW is suppressed by substitution of Sc by larger Lu or Y. Single crystal x-ray diffraction reveals that compressible Sn-Sn bonds accommodate the larger rare earth atoms within loosely packed $R$-Sn-Sn chains without significantly expanding the lattice. We propose that Sc provides the extra room in these chains crucial to CDW formation in ScV$_6$Sn$_6$. Our rattling chain model explains why both physical pressure and substitution by larger rare earths hinder CDW formation despite opposite impacts on lattice size. We emphasize the cooperative effect of pressure and rare earth size by demonstrating that pressure further suppresses the CDW in a Lu-doped ScV$_6$Sn$_6$ crystal. Our model not only addresses why a CDW only forms in the $R$V$_6$Sn$_6$ materials with tiny Sc, it also advances to our understanding of why unusual CDWs form in the kagome metals.


Type-II heavy Fermi liquids and the magnetic memory of 4Hb-TaS$_2$. (arXiv:2306.07871v1 [cond-mat.str-el])
Elio J. König

The interplay of quantum spin liquids with itinerant conduction electrons is of crucial interest for understanding layered structures composed of frustrated magnet and metal monolayers. Using parton-mean-field theory, we here demonstrate that a type-II heavy Fermi liquid, which is characterized by a vortex lattice in the slave boson condensate, can occur in the vicinity of the quantum phase transition separating fractionalized and heavy Fermi liquid phases. The magnetic flux threading each such vortex is about $ v_f/ 137 c$ times smaller than the magnetic flux threading vortices in type-II superconductors, where $v_f$ is the speed of magnetic excitations and $c$ the speed of light. This makes a magnetic observation of this effect challenging. We propose scanning tunneling spectroscopy instead and investigate its signatures. If a type-II heavy Fermi liquid is cooled into a type-II superconductor, vortices in the slave boson condensate and in the superconducting condensate mutually attract. We argue that the type-II heavy Fermi liquid thereby provides a compelling explanation for the magnetic memory observed recently [Persky \textit{et al.}, Nature \textbf{609}, 692 (2022)] in thermal cycles of 4Hb-TaS$_2$.


Weyl Nodes of Opposite Chirality in Ferromagnetic WSM. (arXiv:2306.07882v1 [cond-mat.mes-hall])
Udai Prakash Tyagi, Partha Goswami

The ferromagnetic Weyl semimetals (WSM), such as Co3Sn2S2, are three-dimensional topological states of matter possessing pairs of Weyl points characterized by the opposite chiralities.We model ferromagnetic WSM by a time reversal symmetry(TRS) broken and inversion symmetry protected Bloch Hamiltonian involving index specifying the chirality of the Weyl points, energy parameter determining the shift of the Weyl nodes, terms capturing the tunnelling effect, exchange field in order to take care of the ferromagnetic(FM) order, and the angle formed by the spin moments and the axis perpendicular to the plane of the system. For the FM order along this axis, the bands of opposite chirality almost linearly cross each other (with band inversion) at Weyl points above and below the Fermi level. The in-plane spin order, however, lacks the presence of the Weyl nodes at some points in the Brillouin zone. We also show that, under certain conditions, the incidence of the circularly polarized optical field (CPOF) leads to the emergence of Weyl semimetals from Dirac semimetals due to broken time-reversal symmetry.


Linear Polycatenanes from Kinetoplast Edge Loops. (arXiv:2306.07907v1 [cond-mat.soft])
Josh Ragotskie, Nathaniel Morrison, Christopher Stackhouse, Ryan C. Blair, Alexander R. Klotz

We use graph theory simulations and single molecule experiments to investigate percolation properties of kinetoplasts, the topologically linked mitochondrial DNA from trypanosome parasites. The edges of some kinetoplast networks contain a fiber of redundantly catenated DNA loops, but previous investigations of kinetoplast topology did not take this into account. Our graph simulations track the size of connected components in lattices as nodes are removed, analogous to the removal of minicircles from kinetoplasts. We find that when the edge loop is taken into account, the largest component after the network de-percolates is a remnant of the edge loop, before it undergoes a second percolation transition and breaks apart. This implies that stochastically removing minicircles from kinetoplast DNA would isolate large polycatenanes, which is observed in experiments that use photonicking to stochastically destroy kinetoplasts from Crithidia fasciculata. Our results imply kinetoplasts may be used as a source of linear polycatenanes for future experiments.


Antiferromagnetic real-space configuration probed by dichroism in scattered x-ray beams with orbital angular momentum. (arXiv:2205.03475v2 [cond-mat.mtrl-sci] UPDATED)
Margaret R. McCarter, Ahmad I. U. Saleheen, Arnab Singh, Ryan Tumbleson, Justin S. Woods, Anton S. Tremsin, Andreas Scholl, Lance E. De Long, J. Todd Hastings, Sophie A. Morley, Sujoy Roy

X-ray beams with orbital angular momentum (OAM) are a promising tool for x-ray characterization techniques. Beams with OAM have a helicity--an azimuthally varying phase--which leads to a gradient of the light field. New material properties can be probed by utilizing the helicity of an OAM beam. Here, we demonstrate a novel dichroic effect in resonant diffraction from an artificial antiferromagnet with a topological defect. We found that the scattered OAM beam has circular dichroism at the antiferromagnetic Bragg peak whose sign is coupled to its helicity, which reveals the real-space configuration of the antiferromagnetic ground state. Thermal cycling of the artificial antiferromagnet can change the ground state, as indicated by reversal of the sign of circular dichroism. This result is one of the first demonstrations of a soft x-ray spectroscopy characterization technique utilizing the OAM of x-rays. This helicity-dependent circular dichroism exemplifies the potential to utilize OAM beams to probe matter in a way that is inaccessible using currently available x-ray techniques.


Topology in the space-time scaling limit of quantum dynamics. (arXiv:2301.07752v2 [cond-mat.quant-gas] UPDATED)
Lorenzo Rossi, Jan Carl Budich, Fabrizio Dolcini

We investigate the role of topology in the space-time scaling limit of quantum quench dynamics, where both time and system size tend to infinity at a constant ratio. There, while the standard topological characterization relying on local unitary transformations becomes ill defined, we show how a different dynamical notion of topology naturally arises through a dynamical winding number encoding the linear response of the Berry phase to a magnetic flux. Specifically, we find that the presence of a locally invisible constant magnetic flux is revealed by a dynamical staircase behavior of the Berry phase, whose topologically quantized plateaus characterize the space-time scaling limit of a quenched Rice-Mele model. These jumps in the Berry phase are also shown to be related to the interband elements of the DC current operator. We outline possible experimental platforms for observing the predicted phenomena in finite systems.


Demonstration of the etching cobalt oxide grown on the stainless steel as a base metal surface using F2/He dielectric barrier discharge plasma in atmospheric pressure. (arXiv:2301.09065v2 [physics.plasm-ph] UPDATED)
Mohammad Askari, Nikoo Darestani Farahaniand Mehdi Bakhshzad Mahmoudi, Fereydoun Abbasi Davani

Metal surface cleaning or etching techniques using reactive plasma are emerging as one of the dry processing techniques for surface contaminants with high bond energy, especially for cleaning and decontamination of nuclear components and equipment. In this study, the plasma reaction due to the discharge of a dielectric barrier of a mixture of 95% helium and 5% fluorine with cobalt oxide film grown on the surface of stainless steel 304 was studied experimentally. Experimental results show that cobalt oxide becomes a powder after plasma irradiation and is easily separated from the surface of the base metal. The optimal plasma generating conditions of the dielectric barrier discharge (DBD) used in this experimental study were obtained at atmospheric pressure, voltage 4.5 kV, and frequency 25 kHz with a etching rate of 10.875 {\mu}mol/min. The samples were analyzed before and after plasma irradiation, using Scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDX) and the purification rate was performed using a sequential weighting of the samples with scales 10^(-4) grams accurately obtained. The results show the ability of this method to effectively remove the surface contamination of cobalt from the surface of stainless steel 304.


General scatterings and electronic states in the quantum-wire network of moir\'e systems. (arXiv:2303.00759v2 [cond-mat.mes-hall] UPDATED)
Chen-Hsuan Hsu, Daniel Loss, Jelena Klinovaja

We investigate electronic states in a two-dimensional network consisting of interacting quantum wires, a model adopted for twisted bilayer systems. We construct general operators which describe various scattering processes in the system. In a twisted bilayer structure, the moir\'e periodicity allows for generalized umklapp scatterings, leading to a class of correlated states at certain fractional fillings. We identify scattering processes which can lead to an insulating gapped bulk with gapless chiral edge modes at fractional fillings, resembling the quantum anomalous Hall effect recently observed in twisted bilayer graphene. Finally, the description can be useful in predicting spectroscopic and transport features to detect and characterize the chiral edge modes in the moir\'e-induced correlated states.


Ultrahigh oxygen ion mobility in ferroelectric hafnia. (arXiv:2305.02952v2 [cond-mat.mtrl-sci] UPDATED)
Liyang Ma, Jing Wu, Tianyuan Zhu, Yiwei Huang, Qiyang Lu, Shi Liu

Ferroelectrics and ionic conductors are important functional materials, each supporting a plethora of applications in information and energy technology. The underlying physics governing their functional properties is ionic motion, and yet studies of ferroelectrics and ionic conductors are often considered separate fields. Based on first-principles calculations and deep-learning-assisted large-scale molecular dynamics (MD) simulations, we report ferroelectric-switching-promoted oxygen ion transport in HfO$_2$, a wide-band-gap insulator with both ferroelectricity and ionic conductivity. Applying a unidirectional bias can activate multiple switching pathways in ferroelectric HfO$_2$, leading to polar-antipolar phase cycling that appears to contradict classical electrodynamics. This apparent conflict is resolved by the geometric-quantum-phase nature of electric polarization that carries no definite direction. Our MD simulations demonstrate bias-driven successive ferroelectric transitions facilitate ultrahigh oxygen ion mobility at moderate temperatures, highlighting the potential of combining ferroelectricity and ionic conductivity for the development of advanced materials and technologies.


Magic Angle Butterfly in Twisted Trilayer Graphene. (arXiv:2305.16385v2 [cond-mat.str-el] UPDATED)
Fedor K. Popov, Grigory Tarnopolsky

We consider a configuration of three stacked graphene monolayers with commensurate twist angles $\theta_{12}/\theta_{23}=p/q$, where $p$ and $q$ are coprime integers with $0<p<|q|$ and $q$ can be positive or negative. We study this system using the continuum model in the chiral limit when interlayer coupling terms between $\textrm{AA}_{12}$ and $\textrm{AA}_{23}$ sites of the moir\'{e} patterns $12$ and $23$ are neglected. There are only three inequivalent displacements between the moir\'{e} patterns $12$ and $23$, at which the three monolayers' Dirac zero modes are protected. Remarkably, for these displacements and an arbitrary $p/q$ we discover exactly flat bands at an infinite set of twist angles (magic angles). We provide theoretical explanation and classification of all possible configurations and topologies of the flat bands.


Found 9 papers in prb
Date of feed: Wed, 14 Jun 2023 03:17:04 GMT

Search terms: (topolog[a-z]+)|(graphit[a-z]+)|(rhombohedr[a-z]+)|(graphe[a-z]+)|(chalcog[a-z]+)|(landau)|(weyl)|(dirac)|(STM)|(scan[a-z]+ tunne[a-z]+ micr[a-z]+)|(scan[a-z]+ tunne[a-z]+ spectr[a-z]+)|(scan[a-z]+ prob[a-z]+ micr[a-z]+)|(MoS.+\d+|MoS\d+)|(MoSe.+\d+|MoSe\d+)|(MoTe.+\d+|MoTe\d+)|(WS.+\d+|WS\d+)|(WSe.+\d+|WSe\d+)|(WTe.+\d+|WTe\d+)|(Bi\d+Rh\d+I\d+|Bi.+\d+.+Rh.+\d+.+I.+\d+.+)|(BiTeI)|(BiTeBr)|(BiTeCl)|(ZrTe5|ZrTe.+5)|(Pt2HgSe3|Pt.+2HgSe.+3)|(jacuting[a-z]+)

Ultrafast phonon diffuse scattering as a tool for observing chiral phonons in monolayer hexagonal lattices
Tristan L. Britt and Bradley J. Siwick
Author(s): Tristan L. Britt and Bradley J. Siwick

At the 2D limit, hexagonal systems such as monolayer transition metal dichalcogenides (TMDs) and graphene exhibit unique coupled spin and momentum-valley physics (valley pseudospin) owing to broken spatial inversion symmetry and strong spin-orbit coupling. Circularly polarized light provides the mea…


[Phys. Rev. B 107, 214306] Published Tue Jun 13, 2023

Temperature-induced magnonic Chern insulator in collinear antiferromagnets
Yun-Mei Li, Xi-Wang Luo, and Kai Chang
Author(s): Yun-Mei Li, Xi-Wang Luo, and Kai Chang

Thermal fluctuation in magnets causes temperature-dependent self-energy corrections in magnons; however, its effects on the topological orders of magnons is not well explored. Here we demonstrate that such corrections can induce a Chern insulating phase in two-dimensional collinear antiferromagnets …


[Phys. Rev. B 107, 214417] Published Tue Jun 13, 2023

Interplay between spin wave and magnetic vortex
Zhongchen Gao, Feifei Wang, Xiangyong Zhao, Tao Wang, Jingguo Hu, and Peng Yan
Author(s): Zhongchen Gao, Feifei Wang, Xiangyong Zhao, Tao Wang, Jingguo Hu, and Peng Yan

The interplay between spin wave (SW) and magnetic vortex is studied. We find three types of magnon scatterings: skew scattering, symmetric side deflection, and back reflection, which associate with, respectively, magnetic topology, energy density distribution, and linear momentum transfer torque wit…


[Phys. Rev. B 107, 214418] Published Tue Jun 13, 2023

Multi-$k$ magnetic structure and large anomalous Hall effect in candidate magnetic Weyl semimetal NdAlGe
C. Dhital, R. L. Dally, R. Ruvalcaba, R. Gonzalez-Hernandez, J. Guerrero-Sanchez, H. B. Cao, Q. Zhang, W. Tian, Y. Wu, M. D. Frontzek, S. K. Karna, A. Meads, B. Wilson, R. Chapai, D. Graf, J. Bacsa, R. Jin, and J. F. DiTusa
Author(s): C. Dhital, R. L. Dally, R. Ruvalcaba, R. Gonzalez-Hernandez, J. Guerrero-Sanchez, H. B. Cao, Q. Zhang, W. Tian, Y. Wu, M. D. Frontzek, S. K. Karna, A. Meads, B. Wilson, R. Chapai, D. Graf, J. Bacsa, R. Jin, and J. F. DiTusa

The magnetic structure, magnetoresistance (MR), and Hall effect of the noncentrosymmetric magnetic semimetal NdAlGe are investigated, revealing an unusual magnetic state and anomalous transport properties that are associated with the electronic structure of this compound. The magnetization and MR me…


[Phys. Rev. B 107, 224414] Published Tue Jun 13, 2023

Interacting models for twisted bilayer graphene: A quantum chemistry approach
Fabian M. Faulstich, Kevin D. Stubbs, Qinyi Zhu, Tomohiro Soejima, Rohit Dilip, Huanchen Zhai, Raehyun Kim, Michael P. Zaletel, Garnet Kin-Lic Chan, and Lin Lin
Author(s): Fabian M. Faulstich, Kevin D. Stubbs, Qinyi Zhu, Tomohiro Soejima, Rohit Dilip, Huanchen Zhai, Raehyun Kim, Michael P. Zaletel, Garnet Kin-Lic Chan, and Lin Lin

Twisted bilayer graphene (TBG) has garnered significant interest in condensed matter physics over the past few years. Here, the authors present numerical investigations of TBG implementing state-of-the-art quantum chemistry methods. Using a gauge-invariant order parameter, they show a C2z𝒯 phase transition at charge neutrality which persists at noninteger fillings near charge neutrality. The work is the first systematic study of TBG for noninteger fillings near charge neutrality.


[Phys. Rev. B 107, 235123] Published Tue Jun 13, 2023

Symmetric Wannier states and tight-binding model for quantum spin Hall bands in $AB$-stacked ${\text{MoTe}}_{2}/{\text{WSe}}_{2}$
Xun-Jiang Luo, Minxuan Wang, and Fengcheng Wu
Author(s): Xun-Jiang Luo, Minxuan Wang, and Fengcheng Wu

Motivated by the observation of topological states in $AB$-stacked ${\mathrm{MoTe}}_{2}/{\mathrm{WSe}}_{2}$, we construct the symmetry-adapted Wannier states and tight-binding model for the quantum spin Hall bands in this system. Our construction is based on the symmetry analysis of Bloch states obt…


[Phys. Rev. B 107, 235127] Published Tue Jun 13, 2023

Strain engineering of photoinduced topological phases in two-dimensional ferromagnets
T. V. C. Antão and N. M. R. Peres
Author(s): T. V. C. Antão and N. M. R. Peres

We argue that strain engineering is a powerful tool that may facilitate the experimental realization and control of topological phases in laser-driven two-dimensional (2D) ferromagnetic systems. To this extent, we show that by applying a circularly polarized laser field to a 2D honeycomb ferromagnet…


[Phys. Rev. B 107, 235410] Published Tue Jun 13, 2023

Topological network transport in on-chip phononic crystals
Riyi Zheng, Mou Yan, Jien Wu, Weiyin Deng, Jiuyang Lu, Xueqin Huang, and Zhengyou Liu
Author(s): Riyi Zheng, Mou Yan, Jien Wu, Weiyin Deng, Jiuyang Lu, Xueqin Huang, and Zhengyou Liu

Rapid developments for topological materials have promoted the search for topological transport in the fields of condensed-matter physics and materials science. However, topological network transport, proposed in twisted bilayer graphene and soon after being explored in other two-dimensional materia…


[Phys. Rev. B 107, 245122] Published Tue Jun 13, 2023

Independent and coherent transitions between antiferromagnetic states of few-molecule systems
Claire Besson, Philipp Stegmann, Michael Schnee, Zeila Zanolli, Simona Achilli, Nils Wittemeier, Asmus Vierck, Robert Frielinghaus, Paul Kögerler, Janina Maultzsch, Pablo Ordejón, Claus M. Schneider, Alfred Hucht, Jürgen König, and Carola Meyer
Author(s): Claire Besson, Philipp Stegmann, Michael Schnee, Zeila Zanolli, Simona Achilli, Nils Wittemeier, Asmus Vierck, Robert Frielinghaus, Paul Kögerler, Janina Maultzsch, Pablo Ordejón, Claus M. Schneider, Alfred Hucht, Jürgen König, and Carola Meyer

Molecular spintronics is usually based on paramagnetic or ferromagnetic (S ≠ 0) species. Here, the authors study small ensembles of two molecular antiferromagnets, {Mn4} and {Co4}, bound to carbon nanotube quantum dots. The current through the quantum dots shows a random telegraph signal caused by transitions between nondegenerate Stot = 0 states of individual molecular antiferromagnets. Statistical analysis shows that transitions between those states are independent in the case of {Co4} ensembles, while {Mn4} ensembles display long-lived coherent superposition involving multiple complexes.


[Phys. Rev. B 107, 245414] Published Tue Jun 13, 2023

Found 1 papers in prl
Date of feed: Wed, 14 Jun 2023 03:17:05 GMT

Search terms: (topolog[a-z]+)|(graphit[a-z]+)|(rhombohedr[a-z]+)|(graphe[a-z]+)|(chalcog[a-z]+)|(landau)|(weyl)|(dirac)|(STM)|(scan[a-z]+ tunne[a-z]+ micr[a-z]+)|(scan[a-z]+ tunne[a-z]+ spectr[a-z]+)|(scan[a-z]+ prob[a-z]+ micr[a-z]+)|(MoS.+\d+|MoS\d+)|(MoSe.+\d+|MoSe\d+)|(MoTe.+\d+|MoTe\d+)|(WS.+\d+|WS\d+)|(WSe.+\d+|WSe\d+)|(WTe.+\d+|WTe\d+)|(Bi\d+Rh\d+I\d+|Bi.+\d+.+Rh.+\d+.+I.+\d+.+)|(BiTeI)|(BiTeBr)|(BiTeCl)|(ZrTe5|ZrTe.+5)|(Pt2HgSe3|Pt.+2HgSe.+3)|(jacuting[a-z]+)

Morphotropic Phase Boundary in Polarized Organic Piezoelectric Materials
Fangfang Gao, Xuan Zhao, Xiaochen Xun, Houbing Huang, Xiaoming Shi, Qi Li, Fang Liu, Peng Gao, Qingliang Liao, and Yue Zhang
Author(s): Fangfang Gao, Xuan Zhao, Xiaochen Xun, Houbing Huang, Xiaoming Shi, Qi Li, Fang Liu, Peng Gao, Qingliang Liao, and Yue Zhang

Designing the morphotropic phase boundary (MPB) has been the most sought-after approach to achieve high piezoelectric performance of piezoelectric materials. However, MPB has not yet been found in the polarized organic piezoelectric materials. Here, we discover MPB with biphasic competition of $β$ a…


[Phys. Rev. Lett. 130, 246801] Published Tue Jun 13, 2023

Found 1 papers in pr_res
Date of feed: Wed, 14 Jun 2023 03:17:04 GMT

Search terms: (topolog[a-z]+)|(graphit[a-z]+)|(rhombohedr[a-z]+)|(graphe[a-z]+)|(chalcog[a-z]+)|(landau)|(weyl)|(dirac)|(STM)|(scan[a-z]+ tunne[a-z]+ micr[a-z]+)|(scan[a-z]+ tunne[a-z]+ spectr[a-z]+)|(scan[a-z]+ prob[a-z]+ micr[a-z]+)|(MoS.+\d+|MoS\d+)|(MoSe.+\d+|MoSe\d+)|(MoTe.+\d+|MoTe\d+)|(WS.+\d+|WS\d+)|(WSe.+\d+|WSe\d+)|(WTe.+\d+|WTe\d+)|(Bi\d+Rh\d+I\d+|Bi.+\d+.+Rh.+\d+.+I.+\d+.+)|(BiTeI)|(BiTeBr)|(BiTeCl)|(ZrTe5|ZrTe.+5)|(Pt2HgSe3|Pt.+2HgSe.+3)|(jacuting[a-z]+)

Propagation of Dirac waves through various temporal interfaces, slabs, and crystals
Seulong Kim and Kihong Kim
Author(s): Seulong Kim and Kihong Kim

We investigate the influence of the temporal variations of various medium parameters on the propagation of Dirac-type waves in materials where the quasiparticles are described by a generalized version of the pseudospin-1/2 Dirac equation. Our considerations also include the propagation of electromag…


[Phys. Rev. Research 5, 023162] Published Tue Jun 13, 2023

Found 2 papers in nano-lett
Date of feed: Tue, 13 Jun 2023 20:59:11 GMT

Search terms: (topolog[a-z]+)|(graphit[a-z]+)|(rhombohedr[a-z]+)|(graphe[a-z]+)|(chalcog[a-z]+)|(landau)|(weyl)|(dirac)|(STM)|(scan[a-z]+ tunne[a-z]+ micr[a-z]+)|(scan[a-z]+ tunne[a-z]+ spectr[a-z]+)|(scan[a-z]+ prob[a-z]+ micr[a-z]+)|(MoS.+\d+|MoS\d+)|(MoSe.+\d+|MoSe\d+)|(MoTe.+\d+|MoTe\d+)|(WS.+\d+|WS\d+)|(WSe.+\d+|WSe\d+)|(WTe.+\d+|WTe\d+)|(Bi\d+Rh\d+I\d+|Bi.+\d+.+Rh.+\d+.+I.+\d+.+)|(BiTeI)|(BiTeBr)|(BiTeCl)|(ZrTe5|ZrTe.+5)|(Pt2HgSe3|Pt.+2HgSe.+3)|(jacuting[a-z]+)

[ASAP] Trion Formation Resolves Observed Peak Shifts in the Optical Spectra of Transition-Metal Dichalcogenides
Thomas Sayer, Yusef R. Farah, Rachelle Austin, Justin Sambur, Amber T. Krummel, and Andrés Montoya-Castillo

TOC Graphic

Nano Letters
DOI: 10.1021/acs.nanolett.3c01342

[ASAP] Graphene Hybrid Inner Ear Organoid with Enhanced Maturity
Sunho Park, Yeon Ju Kim, Harshita Sharma, Dream Kim, Yonghyun Gwon, Woochan Kim, Sangbae Park, Cheol Woo Ha, Yun-Hoon Choung, and Jangho Kim

TOC Graphic

Nano Letters
DOI: 10.1021/acs.nanolett.3c00988

Found 1 papers in science-adv
Date of feed: Tue, 13 Jun 2023 19:04:02 GMT

Search terms: (topolog[a-z]+)|(graphit[a-z]+)|(rhombohedr[a-z]+)|(graphe[a-z]+)|(chalcog[a-z]+)|(landau)|(weyl)|(dirac)|(STM)|(scan[a-z]+ tunne[a-z]+ micr[a-z]+)|(scan[a-z]+ tunne[a-z]+ spectr[a-z]+)|(scan[a-z]+ prob[a-z]+ micr[a-z]+)|(MoS.+\d+|MoS\d+)|(MoSe.+\d+|MoSe\d+)|(MoTe.+\d+|MoTe\d+)|(WS.+\d+|WS\d+)|(WSe.+\d+|WSe\d+)|(WTe.+\d+|WTe\d+)|(Bi\d+Rh\d+I\d+|Bi.+\d+.+Rh.+\d+.+I.+\d+.+)|(BiTeI)|(BiTeBr)|(BiTeCl)|(ZrTe5|ZrTe.+5)|(Pt2HgSe3|Pt.+2HgSe.+3)|(jacuting[a-z]+)

In-plane anisotropy of graphene by strong interlayer interactions with van der Waals epitaxially grown MoO3
Hangyel Kim, Jong Hun Kim, Jungcheol Kim, Jejune Park, Kwanghee Park, Ji-Hwan Baek, June-Chul Shin, Hyeongseok Lee, Jangyup Son, Sunmin Ryu, Young-Woo Son, Hyeonsik Cheong, Gwan-Hyoung Lee
Science Advances, Volume 9, Issue 23, June 2023.

Found 1 papers in sci-rep


Search terms: (topolog[a-z]+)|(graphit[a-z]+)|(rhombohedr[a-z]+)|(graphe[a-z]+)|(chalcog[a-z]+)|(landau)|(weyl)|(dirac)|(STM)|(scan[a-z]+ tunne[a-z]+ micr[a-z]+)|(scan[a-z]+ tunne[a-z]+ spectr[a-z]+)|(scan[a-z]+ prob[a-z]+ micr[a-z]+)|(MoS.+\d+|MoS\d+)|(MoSe.+\d+|MoSe\d+)|(MoTe.+\d+|MoTe\d+)|(WS.+\d+|WS\d+)|(WSe.+\d+|WSe\d+)|(WTe.+\d+|WTe\d+)|(Bi\d+Rh\d+I\d+|Bi.+\d+.+Rh.+\d+.+I.+\d+.+)|(BiTeI)|(BiTeBr)|(BiTeCl)|(ZrTe5|ZrTe.+5)|(Pt2HgSe3|Pt.+2HgSe.+3)|(jacuting[a-z]+)

Author Correction: MircoRNA-145 promotes activation of hepatic stellate cells via targeting krüppel-like factor 4
Li Yang

Scientific Reports, Published online: 13 June 2023; doi:10.1038/s41598-023-36674-4

Author Correction: MircoRNA-145 promotes activation of hepatic stellate cells via targeting krüppel-like factor 4

Found 2 papers in nat-comm


Search terms: (topolog[a-z]+)|(graphit[a-z]+)|(rhombohedr[a-z]+)|(graphe[a-z]+)|(chalcog[a-z]+)|(landau)|(weyl)|(dirac)|(STM)|(scan[a-z]+ tunne[a-z]+ micr[a-z]+)|(scan[a-z]+ tunne[a-z]+ spectr[a-z]+)|(scan[a-z]+ prob[a-z]+ micr[a-z]+)|(MoS.+\d+|MoS\d+)|(MoSe.+\d+|MoSe\d+)|(MoTe.+\d+|MoTe\d+)|(WS.+\d+|WS\d+)|(WSe.+\d+|WSe\d+)|(WTe.+\d+|WTe\d+)|(Bi\d+Rh\d+I\d+|Bi.+\d+.+Rh.+\d+.+I.+\d+.+)|(BiTeI)|(BiTeBr)|(BiTeCl)|(ZrTe5|ZrTe.+5)|(Pt2HgSe3|Pt.+2HgSe.+3)|(jacuting[a-z]+)

Author Correction: Ising superconductivity induced from spin-selective valley symmetry breaking in twisted trilayer graphene
< author missing >

Imaging and controlling coherent phonon wave packets in single graphene nanoribbons
< author missing >