Optical Response Characteristics of the Weyl Semimetals WTe₂ and MoTe₂

Weyl semimetals are 3D systems exhibiting linear dispersion band crossings which act as Berry curvature monopoles in the reciprocal space. A key signature for Weyl semimetals is the appearance of surface Fermi arcs as a result of the projection of the bulk Weyl points on the surface of the material. Here we report first-principles calculations for the dynamical conductivity tensor, a basic quantity for the light-matter interactions, of the Weyl semimetals MoTe₂ and WTe₂. The calculations rely on the Kubo formula, computed based on a Wannier interpolation scheme, which takes into account the realistic electronic structure of these materials. The different components of the optical conductivity tensor are determined and studied as a function of frequency. Contributions from the bulk and surface states of the studied materials are also distinguished. The relation of the calculated results with the experimental ones, as well as the temperature effects, are also discussed.