Anisotropic longitudinal optical conductivities of tilted Dirac bands in 1T′-MoS2

1T'-MoS2 exhibits valley-spin-polarized tilted Dirac bands in the presence of external vertical electric field and undergoes a topological phase transition between the topological insulator and band insulator around the critical value of the electric field. Within the linear response theory, we theoretically investigate the anisotropic longitudinal optical conductivities of tilted Dirac bands in both undoped and doped 1T'-MoS2, including the effects of the vertical electric field. The influence of the spin-orbit coupling gap, band tilting, and vertical electric field on the optical conductivities of tilted Dirac bands is revealed. A theoretical scheme for probing the topological phase transition in 1T'-MoS2 via exotic behaviors of longitudinal optical conductivities is proposed. The results for 1T'-MoS2 are expected to be qualitatively valid for other monolayer tilted gapped Dirac materials, such as alpha-SnS2, TaCoTe2, and TaIrTe4, due to the similarity in their band structures.

Automated summary

We theoretically investigate the anisotropic longitudinal optical conductivities of tilted Dirac bands in 1T'-MoS2, revealing the influences of spin-orbit coupling gap, band tilting, and vertical electric field on the optical conductivities. A theoretical scheme for probing the topological phase transition in 1T'-MoS2 via exotic behaviors of longitudinal optical conductivities is proposed. The results for 1T'-MoS2 are expected to be qualitatively valid for other monolayer tilted gapped Dirac materials.