Design principles of 3D Dirac semimetals and tilted Dirac Fermions in 2D

Wednesday, 22 May 2016, at 11:15 in Y36 J33

I will present design principles and predictions of new three-dimensional (3D) Dirac semimetals in the context of currently known materials. Three different design principles are presented, each of which yields predictions for new candidates. We then switch to two-dimensional Dirac materials and introduce the notion of type-II Dirac Fermions which arise due to the tilting of a 2D Dirac cone. These new Dirac Fermions can be found in monolayers of MoTe$_2$ and WTe$_2$ if spin-orbit coupling is neglected. In these materials, type-II Dirac Fermions appear as a consequence of a novel type of topological metal due to a band inversion protected by nonsymmorphic symmetries.