Valley-controlled Transport in Graphene WSe2 Heterostructures under Off-Resonant Polarized Light

We investigate the electronic dispersion and transport properties of graphene/WSe2 heterostructures in the presence of a proximity-induced spin-orbit coupling lambda(u), sublattice potential Delta, and an off-resonant circularly polarized light of frequency St that renormalizes Delta to (Delta) over bar (eta p) = Delta + eta p Delta(Omega) with eta and p the valley and polarization indices, respectively, and Delta(Omega) the gap due to the off-resonant circularly polarized light. Using a low-energy Hamiltonian we find that the interplay between different perturbation terms leads to inverted spin-orbit coupled bands. At high St we study the band structure and dc transport using the Floquet theory and linear response formalism, respectively. We find that the inverted band structure transfers into the direct band one when the off-resonant light is present. The valley-Hall conductivity behaves as an even function of the Fermi energy in the presence and absence of this light. At Delta(Omega) = lambda(u) - Delta, a transition occurs from the valley-Hall phase to the anomalous Hall phase. In addition, the valley-Hall conductivity switches sign when the polarization of the off-resonant light changes. The valley polarization vanishes for Delta(Omega) = 0 but it is finite for Delta(Omega )not equal 0 and reflects the lifting of the valley degeneracy of the energy levels, for Delta(Omega) = 0, when the off-resonant light is present. The corresponding spin polarization, present for Delta(Omega) = 0, increases for Delta(Omega) not equal 0. Further, pure K or K' valley polarization is generated when 4 2 changes sign. Also, the charge Hall conductivity is finite for Delta(Omega) not equal 0 and changes sign when the handedness of the light polarization changes.