Intersubband electric dipole spin resonance in transition metal dichalcogenide heterobilayers

TL;DR

This paper proposes a theory for electric dipole spin resonance in transition metal dichalcogenide heterobilayers, highlighting how reduced symmetry enables electric field coupling between spin subbands.

Contribution

It introduces a symmetry-based theoretical framework and identifies the microscopic mechanism for electric dipole spin resonance in heterobilayers, including selection rules and the Rashba effect.

Findings

Electric-dipole spin-flip transitions are much faster than magnetic ones.

Symmetry analysis reveals coupling between conduction band spin subbands via electric fields.

The mechanism involves spin-orbit coupling induced mixing and Rashba-type effects.

Abstract

The theory of inter-spin-subband electric dipole spin resonance in transition metal dichalcogenide heterobilayers is proposed. Our symmetry analysis demonstrates that, in contrast to monolayers, the reduced symmetry of heterobilayers enables coupling between conduction band spin subbands by an electric field. We establish the optical selection rules for all six high-symmetry stacking configurations. The microscopic mechanism of the effect is identified as the spin-orbit coupling induced mixing of Bloch states from different conduction bands, which generates a non-zero momentum matrix element between the spin-split states. It also leads to the linear-in-wavevector spin-dependent terms in the effective Hamiltonian, i.e., the Rashba effect. Our estimates show that the rate of electric-dipole spin-flip transitions exceeds by far that of the magnetic-dipole transitions in transition metal dichalcogenide heterobilayers.