Valley spin-acoustic resonance in MoS2 monolayers

Abstract

The band structure of a monolayer MoS2 comprises spin-split subbands, owing to the mutual presence of broken inversion symmetry and strong spin-orbit coupling. In the conduction band, spin-valley coupled subbands cross each other at finite momenta, and they are valley degenerate. When exposed to surface acoustic waves, the emerging strain-induced effective magnetic fields can give rise to spin-flip transitions between the spin-split subbands in the vicinity of the subband crossing point, resulting in the emergence of a spin-acoustic resonance and the acoustoelectric current. Resonance peaks occur at acoustic frequencies of gigahertz range in the vicinity of the subband crossing point. An external magnetic field breaks the valley degeneracy, resulting in the valleyselective splitting of spin-acoustic resonances, both in surface acoustic wave absorption and acoustoelectric current.