Magneto-optical properties of bilayer transition metal dichalcogenides

Abstract

In transition metal dichalcogenides the spin-orbit interaction affects differently the conduction and valence band energies as functions of k and the band gap is large. Consequently, when a perpendicular magnetic field B is applied the conduction and valence band Landau levels are also different and this leads to a splitting of the interband optical absorption lines in both the absence and presence of an external electric field Ez. When B and Ez are present the peaks in the imaginary part of the Hall conductivity give two distinct contributions of opposite sign to the interband spectrum. The real part of the right-and left-handed interband conductivity, however, retains its two-peak structure but the peaks are shifted in energy and amplitude with respect to each other in contrast with graphene. The response of the intraband conductivity is significantly modified when the Fermi energy EF and the field B are varied. Its optical spectral weight is found to increase with EF in contrast with the decrease observed in graphene. Further, the position and amplitude of the intraband response depends on the field B. The absorption peaks vary linearly with B for all fields similar to bilayer graphene for low fields but in contrast with the high-field √ B dependence in it.

Photoinduced electronic and spin properties of two-dimensional electron gases with Rashba spin-orbit coupling under perpendicular magnetic fields

“…where is the photon frequency and is a parameter describing the effective Floquet-Landau level broadening due to residual scattering of the electron with impurities [28,[45][46][47]. To simplify the notation, we have defined in Eq.…”

High-efficiency spin and valley filter in a monolayer WSe2 superlattice modulated by an anti-handed off-resonance circularly polarized light

“…Recently, ML transition metal dichalcogenides (TMDCs) [15][16][17][18][19] have received extensive attention since they were experimentally synthesized, and have provided a convenient platform for developing future nanoelectronic devices due to their distinct physical characteristics, such as reasonable inplane carrier mobility rate, high thermal stability and good compatibility with standard semiconductor processes [15,17,[20][21][22]. As a representative of TMDCs, monolayer WSe 2 (ML WSe 2 ) possesses a relatively large band gap (=1.7 eV) [23][24][25] and strong spin-orbit coupling (SOC) [26][27][28] of 450 (30) meV in the valence (conduction) band edge. Therefore, these excellent properties render ML WSe 2 as a promising candidate for designing superlattices to research spin-valley transport.…”