Our paper on Pt2HgSe3 has been published in Nano Letters

Pt2HgSe3 is a layered, van der Waals mineral, called jacutingaite. It was discovered in 2008 in Brazil [1] and the monolayer has been predicted to be a large gap topological insulator [2]. Our group has been able to detect signatures of the predicted topological edge states, within a bulk gap that is larger than 100 meV. Interestingly, the bands leading to the topological gap and edge states stem from a honeycomb layer of Hg and Pt (see image below), making jacutingaite a “heavy metal” version of graphene, ie. an example of the long sought after Kane-Mele insulator [3].

Jacutingaite combines a truly unique set of properties in one material. It is a room temperature topological insulator, that is stable under ambient conditions and can be exfoliated to few layers, using the same techniques that have been applied with success to other van der Waals materials.

With the prediction of superconductivity [4,5] and the dual topological nature of the material [6,7], there is still a lot of interesting physics to be explored here.

Atomic resolution STM image of the jacutingaite (Pt2HgSe3) basal plane. Atomic lattice, showing the Pt-Hg “heavy metal graphene” lattice of the material

Kandrai, K. et al. Signature of large-gap quantum spin Hall state in the layered mineral jacutingaite. Nano Lett. 20, 5207–5213 (2020)

[1] Cabral, A. R., Galbiatti, H. F., Kwitko-Ribeiro, R. & Lehmann, B. Platinum enrichment at low temperatures and related microstructures, with examples of hongshiite (PtCu) and empirical ‘Pt2HgSe3’ from Itabira, Minas Gerais, Brazil. Terra Nov. 20, 32–37 (2008).
[2] Marrazzo, A., Gibertini, M., Campi, D., Mounet, N. & Marzari, N. Prediction of a Large-Gap and Switchable Kane-Mele Quantum Spin Hall Insulator. Phys. Rev. Lett. 120, 117701 (2018).
[3] Kane, C. L. & Mele, E. J. Quantum Spin Hall Effect in Graphene. Phys. Rev. Lett. 95, 226801 (2005).
[4] Wu, X., Fink, M., Hanke, W., Thomale, R. & Di Sante, D. Unconventional superconductivity in a doped quantum spin Hall insulator. Phys. Rev. B 100, 041117 (2019).
[5] Ghosh, B. et al. Saddle-point Van Hove singularity and dual topological state in Pt 2 HgSe 3 . Phys. Rev. B 100, 235101 (2019).
[6] Facio, J. I. et al. Dual topology in jacutingaite Pt2HgSe3. Phys. Rev. Mater. 3, 074202 (2019).
Marrazzo, A., Marzari, N. & Gibertini, M. Emergent dual topology in the three-dimensional Kane-Mele Pt2HgSe3. Phys. Rev. Res. 2, 012063 (2020).