FLEET seminar. In silico discovery of novel topological materials

Prof. Oleg V. Yazyev, Institute of Physics, École Polytechnique Fédérale de Lausanne (EPFL)

In person: G30, New Horizons Bld, Monash University, 20 Research Way, Clayton

Catch the recorded seminar on YouTube

In my talk, I will focus on our recent efforts directed towards the search of novel topological materials. A large number of diverse topological electronic phases that can be realized in materials have been predicted recently. We have developed a high-throughput computational screening methodology for identifying materials hosting various topological phases among known materials. The entire dataset of results obtained using this high-throughput search is now publicly available via the Materials Cloud platform [1]. Several predictions resulting from this search have been successfully confirmed by experiments. A new Z₂ topological insulator was theoretically predicted and experimentally confirmed in the β-phase of quasi-one-dimensional bismuth iodide Bi₄I₄ [2]. The electronic structure of β-Bi₄I₄, characterized by Z₂ invariants (1;110), is in proximity of both the weak TI phase (0;001) and the trivial insulator phase (0;000). We further predicted robust type-II Weyl semimetal phase in transition metal diphosphides MoP₂ and WP₂ characterized by very large momentum-space separation between Weyl points of opposite chirality [3]. Recent experiments on WP₂ revealed record magnitudes of magnetoresistance combined with very high conductivity and residual resistivity ratio [4], and many other extraordinary properties. I will discuss in detail the physical mechanism underlying magnetotransport in WP₂ as well as in other trivial and topological semimetals [5].

Prof. Oleg Yazyev’s research focuses on the theoretical and computational physics of two-dimensional and topological materials with a strong emphasis on their prospective technological applications. In September 2011 he started an independent research group at EPFL  supported by the Swiss National Science Foundation professorship grant. In 2012 he was awarded an ERC Starting grant.

[1] G. Autès, Q. S. Wu, N. Mounet, and O. V. Yazyev, “TopoMat: a database of high-throughput first-principles calculations of topological materials”, https://www.materialscloud.org/discover/topomat

[2] G. Autès et al., Nature Mater. 15, 154 (2016).

[3] G. Autès, D. Gresch, M. Troyer, A. A. Soluyanov and O. V. Yazyev, Phys. Rev. Lett. 117, 066402 (2016).

[4] N. Kumar et al., Nature Commun. 8, 1642 (2017).

[5] S. N. Zhang, Q. S. Wu, Y. Liu and O. V. Yazyev, Phys. Rev. B 99, 035142 (2019).