Spin-resolved optical conductivity of two-dimensional group-VIB transition-metal dichalcogenides

TL;DR

This paper provides a detailed ab-initio analysis of the spin-resolved optical conductivity in 2D group-VIB transition-metal dichalcogenides, revealing precise band features and the influence of saddle points on optical responses.

Contribution

It introduces a high-resolution, fully-relativistic computational approach to accurately locate van Hove singularities in 2D TMDs' optical spectra.

Findings

Identification of saddle points not aligned with high-symmetry directions

High-precision mapping of van Hove singularities in 2D TMDs

Insights into the photo-response to circularly polarized light

Abstract

We present an ab-initio study of the spin-resolved optical conductivity of two-dimensional (2D) group-VIB transition-metal dichalcogenides (TMDs). We carry out fully-relativistic density-functional-theory calculations combined with maximally localized Wannier functions to obtain band manifolds at extremely high resolutions and focus on the photo-response of 2D TMDs to circularly-polarized light in a wide frequency range. We present extensive numerical results for monolayer TMDs involving molybdenum and tungsten combined with sulphur and selenium. Our numerical approach allows us to locate with a high degree of accuracy the positions of the points in the Brillouin zone that are responsible for van Hove singularities in the optical response. Surprisingly, some of the saddle points do not occur exactly along high-symmetry directions in the Brillouin zone, although they happen to be in their close proximity.