TY - JOUR
T1 - Influence of lattice termination on the edge states of the quantum spin Hall insulator monolayer 1T′-WTe2
AU - Lau, Alexander
AU - Ray, Rajyavardhan
AU - Varjas, Dániel
AU - Akhmerov, Anton R.
PY - 2019
Y1 - 2019
N2 - 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 four-orbital tight-binding model with spin-orbit coupling by employing a combination of density-functional theory calculations, symmetry considerations, and fitting to experimental data. Based on this model, we compute energy bands and two-terminal conductance spectra for various ribbon geometries with different terminations, with and without a 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.
AB - 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 four-orbital tight-binding model with spin-orbit coupling by employing a combination of density-functional theory calculations, symmetry considerations, and fitting to experimental data. Based on this model, we compute energy bands and two-terminal conductance spectra for various ribbon geometries with different terminations, with and without a 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.
UR - http://www.scopus.com/inward/record.url?scp=85066789765&partnerID=8YFLogxK
U2 - 10.1103/PhysRevMaterials.3.054206
DO - 10.1103/PhysRevMaterials.3.054206
M3 - Article
AN - SCOPUS:85066789765
SN - 2475-9953
VL - 3
JO - Physical Review Materials
JF - Physical Review Materials
IS - 5
M1 - 054206
ER -