TY - JOUR
T1 - Magnetic field control of light-induced spin accumulation in monolayer MoSe2
AU - Rojas-Lopez, Rafael R.
AU - Hendriks, Freddie
AU - van der Wal, Caspar H.
AU - Guimarães, Paulo S. S.
AU - Guimarães, Marcos H. D.
N1 - Funding Information:
We thank J G Holstein, H de Vries, F van der Velde, H Adema, and A Joshua for their technical support. This work was supported by the Dutch Research Council (NWO—STU.019.014), the Zernike Institute for Advanced Materials, and the Brazilian funding agencies CNPq, FAPEMIG and the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior—Brasil (CAPES) - Project code 88887.476316/2020-00.
Publisher Copyright:
© 2023 IOP Publishing Ltd.
PY - 2023/7
Y1 - 2023/7
N2 - 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.
AB - 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.
KW - magneto-optic Kerr effect
KW - MoSe monolayer
KW - spin dynamics
KW - transition metal dichalcogenides
KW - two-dimensional materials
KW - ultrafast optics
UR - http://www.scopus.com/inward/record.url?scp=85159154610&partnerID=8YFLogxK
U2 - 10.1088/2053-1583/acd12a
DO - 10.1088/2053-1583/acd12a
M3 - Article
AN - SCOPUS:85159154610
SN - 2053-1583
VL - 10
JO - 2D Materials
JF - 2D Materials
IS - 3
M1 - 035013
ER -