We introduce the notion of a band-inverted, topological semimetal in two-dimensional nonsymmorphic crystals. This notion is materialized in the monolayers of MTe2 (M = W, Mo) if spin-orbit coupling is neglected. We characterize the Dirac band touching topologically by the Wilson loop of the non-Abelian Berry gauge field. An additional feature of the Dirac cone in monolayer MTe2 is that it tilts over in a Lifshitz transition to produce electron and hole pockets, a type-II Dirac cone. These pockets, together with the pseudospin structure of the Dirac electrons, suggest a unified, topological explanation for the recently-reported, non-saturating magnetoresistance in WTe2, as well as its circular dichroism in photoemission. We complement our analysis and first-principle bandstructure calculations with an ab-initio-derived-derived tight-binding model for the WTe2 monolayer.
@article{arxiv.1604.01398,
title = {Tilted Dirac Fermions},
author = {Lukas Muechler and Aris Alexandradinata and Titus Neupert and Roberto Car},
journal= {arXiv preprint arXiv:1604.01398},
year = {2017}
}
Comments
Changed Title, improved introduction and added references