Strong cavity-pseudospin coupling in monolayer transition metal dichalcogenides
AbstractStrong coupling between the electronic states of monolayer transition metal dichalcogenides (TMDCs) such as MoS2,MoSe2,WS2, or WSe2, and a single in-plane optical cavity mode gives rise to valley- and spin-dependent cavity-QED effects. The Dirac Hamiltonian for this two-dimensional gapped semiconductor with large spin-orbit coupling facilitates pure Jaynes-Cummings-type coupling with spin-valley locking—providing an additional handle for spintronics using circularly polarized light. Besides being an on-chip light source, the strong cavity coupling causes the TMDC monolayer to act as a spontaneous spin oscillator. In addition, this system can be a sensitive magnetic field sensor for an in-plane magnetic field. It also displays unusual persistent Rabi oscillations between different conduction-band states that are insensitive to small magnetic field variations. Our analysis for dissipation due to finite exciton relaxation times and cavity losses suggests that these effects are observable.