Magnetic field control of light-induced spin accumulation in monolayer MoSe2

Rafael R. Rojas-Lopez*, Freddie Hendriks, Caspar H. van der Wal, Paulo S. S. Guimarães, Marcos H. D. Guimarães*

*Bijbehorende auteur voor dit werk

OnderzoeksoutputAcademicpeer review

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Semiconductor transition metal dichalcogenides (TMDs) have equivalent dynamics for their two spin/valley species. This arises from their energy-degenerated spin states, connected via time-reversal symmetry. When an out-of-plane magnetic field is applied, time-reversal symmetry is broken and the energies of the spin-polarized bands shift, resulting in different bandgaps and dynamics in the K + and K − valleys. Here, we use time-resolved Kerr rotation to study the magnetic field dependence of the spin dynamics in monolayer MoSe2. We show that the magnetic field can control the light-induced spin accumulation of the two valley states, with a small effect on the recombination lifetimes. We unveil that the magnetic field-dependent spin accumulation is in agreement with hole spin dynamics at the longer timescales, indicating that the electron spins have faster relaxation rates. We propose a rate equation model that suggests that lifting the energy-degeneracy of the valleys induces an ultrafast spin-flip toward the stabilization of the valley with the higher valence band energy. Our results provide an experimental insight into the ultrafast charge and spin dynamics in TMDs and a way to control it, which will be useful for the development of new spintronic and valleytronic applications.

Originele taal-2English
Aantal pagina's7
Tijdschrift2D Materials
Nummer van het tijdschrift3
StatusPublished - jul.-2023

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