Journal Article

FZJ-2020-02155

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Spin States Protected from Intrinsic Electron–Phonon Coupling Reaching 100 ns Lifetime at Room Temperature in MoSe 2

Ersfeld, M.RWTH* ; Volmer, F.RWTH* ; de Melo, P. M. M. C. ; de Winter, R.FZJ* ; Heithoff, M.FZJ* ; Zanolli, Z. ; Stampfer, C.FZJ*RWTH* ; Verstraete, M. J. ; Beschoten, B. (Corresponding author)RWTH*FZJ*

2019
ACS Publ. Washington, DC

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Please use a persistent id in citations: http://hdl.handle.net/2128/25023  doi:10.1021/acs.nanolett.9b01485

Abstract: We present time-resolved Kerr rotation measurements, showing spin lifetimes of over 100 ns at room temperature in monolayer MoSe2. These long lifetimes are accompanied by an intriguing temperature-dependence of the Kerr amplitude, which increases with temperature up to 50 K and then abruptly switches sign. Using ab initio simulations, we explain the latter behavior in terms of the intrinsic electron–phonon coupling and the activation of transitions to secondary valleys. The phonon-assisted scattering of the photoexcited electron–hole pairs prepares a valley spin polarization within the first few ps after laser excitation. The sign of the total valley magnetization, and thus the Kerr amplitude, switches as a function of temperature, as conduction and valence band states exhibit different phonon-mediated intervalley scattering rates. However, the electron–phonon scattering on the ps time scale does not provide an explanation for the long spin lifetimes. Hence, we deduce that the initial spin polarization must be transferred into spin states, which are protected from the intrinsic electron–phonon coupling, and are most likely resident charge carriers, which are not part of the itinerant valence or conduction band states.

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Contributing Institute(s):

1. Halbleiter-Nanoelektronik (PGI-9)
2. JARA-FIT (JARA-FIT)

Research Program(s):

1. 522 - Controlling Spin-Based Phenomena (POF3-522) (POF3-522)

Appears in the scientific report 2020

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; ; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; Ebsco Academic Search ; Essential Science Indicators ; IF >= 10 ; JCR ; NCBI Molecular Biology Database ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Web of Science Core Collection

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