2024/07/09 by D. Lagarde, M. M. Glazov, Lagarde, D. +21 · 4 citations
Materials Science · Physics and Astronomy · #2D Materials and Applications #FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Other Condensed Matter (cond-mat.other) #Quantum and electron transport phenomena #Solid-state spectroscopy and crystallography
paper · pdf · doi:10.48550/arxiv.2407.07188
openalex publication_date 2024/07/09 · openalex created_date 2024/07/13 · openalex updated_date 2026/07/30
In transition metal dichalcogenide semiconductor monolayers the spin dynamics of electrons is controlled by the original spin-valley locking effect resulting from the interplay between spin-orbit interaction and inversion asymmetry. As a consequence, for electrons occupying bottom conduction bands, a carrier spin flip occurs only if there is a simultaneous change of valley. However, very little is known about the intra-valley spin relaxation processes. In this work we have performed stationary and time-resolved photoluminescence measurements in high quality WSe2 monolayers. Our experiments highlight an efficient relaxation from bright to dark excitons, due to a fast intra-valley electron transfer from the top to the bottom conduction band with opposite spins. A combination of experiments and theoretical analysis allows us to infer a spin relaxation time of about τs∼10~ps, driven by the interplay between Γ-valley chiral phonons and spin-orbit mixing.