We study the influence of sample termination on the electronic properties of the novel quantum spin Hall insulator monolayer 1T -WTe2. For this purpose, we construct an accurate, minimal 4-orbital tight-binding model with spin-orbit coupling by employing a combination of densityfunctional theory calculations, symmetry considerations, and fitting to experimental data. Based on this model, we compute energy bands and 2-terminal conductance spectra for various ribbon geometries with different terminations, with and without magnetic field. Because of the strong electron-hole asymmetry we find that the edge Dirac point is buried in the bulk bands for most edge terminations. In the presence of a magnetic field, an in-gap edge Dirac point leads to exponential suppression of conductance as an edge Zeeman gap opens, whereas the conductance stays at the quantized value when the Dirac point is buried in the bulk bands. Finally, we find that disorder in the edge termination drastically changes this picture: the conductance of a sufficiently rough edge is uniformly suppressed for all energies in the bulk gap regardless of the orientation of the edge.
II. TIGHT-BINDING MODEL FOR MONOLAYER WTE2WTe 2 is a member of the transition metal dichalcogenide family of materials. Single layers in this materials class crystallize in a variety of polytypic structures such as the hexagonal 2H, the tetragonal 1T , and the distorted 1T structure. 16,44,45 While the former represent trivial semiconductors, the 1T configuration gives rise arXiv:1812.05693v3 [cond-mat.mes-hall]