Spin-valley relaxation dynamics of Landau-quantized electrons in MoSe₂ monolayer

Transition metal dichalcogenide monolayers provide a fascinating experimental platform for optical investigations of strongly correlated electronic states. Although the formation of such states has been evidenced in explorations of electronic ground state properties [1], the effects of strong correlations on non-equilibrium dynamics remained elusive. In this talk I will review our recent studies of spin-valley relaxation of electrons in charge-controlled MoSe₂ monolayer under the influence of strong out-of-plane magnetic field that quantizes the electronic bands into Landau levels (LLs) [2]. The electron spins are optically depolarized with excitons injected by a short light pulse and the spin-valley relaxation rate is measured in pump-probe experiments. Our results evidence that the relaxation dynamics at temperatures below 100 mK displays prominent oscillations with the LL filling factor: it speeds up when the electrons form an uncorrelated integer quantum Hall state and slows down at non-integer fillings, when the electronic correlations become more prominent. This observation indicates that spin-valley relaxation dynamics may be exploited to study the effects of strong inter-electron interactions in the electronic ground state of an atomically-thin semiconductor.