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Title: Gate-Controlled Spin-Valley Locking of Resident Carriers in WSe 2 Monolayers

Using time-resolved Kerr rotation, we measure the spin-valley dynamics of resident electrons and holes in single charge-tunable monolayers of the archetypal transition-metal dichalcogenide (TMD) semiconductor WSe 2. In the n-type regime, we observe long (~ 130 ns) polarization relaxation of electrons that is sensitive to in-plane magnetic fields B y, indicating spin relaxation. In marked contrast, extraordinarily long (~ 2 μs) polarization relaxation of holes is revealed in the p-type regime, which is unaffected by B y, directly confirming long-standing expectations of strong spin-valley locking of holes in the valence band of monolayer TMDs. Finally, supported by continuous-wave Kerr spectroscopy and Hanle measurements, these studies provide a unified picture of carrier polarization dynamics in monolayer TMDs, which can guide design principles for future valleytronic devices.
Authors:
ORCiD logo [1] ;  [1] ;  [2] ;  [2] ;  [2] ;  [2] ;  [1]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  2. Univ. de Toulouse,Toulouse (France)
Publication Date:
Report Number(s):
LA-UR-17-21735
Journal ID: ISSN 0031-9007; PRLTAO
Grant/Contract Number:
AC52-06NA25396; 306719
Type:
Accepted Manuscript
Journal Name:
Physical Review Letters
Additional Journal Information:
Journal Volume: 119; Journal Issue: 13; Journal ID: ISSN 0031-9007
Publisher:
American Physical Society (APS)
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
National Science Foundation (NSF); European Research Council (ERC); USDOE
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; High Magnetic Field Science; Transition-Metal Dichalcogenide; TMD; Valleytronic
OSTI Identifier:
1471348
Alternate Identifier(s):
OSTI ID: 1395189

Crooker, Scott A., Yang, Luyi, Robert, Cedric, Wang, Gang, Urbaszek, Bernhard, Marie, Xavier, and Dey, Prasenjit. Gate-Controlled Spin-Valley Locking of Resident Carriers in WSe2 Monolayers. United States: N. p., Web. doi:10.1103/PhysRevLett.119.137401.
Crooker, Scott A., Yang, Luyi, Robert, Cedric, Wang, Gang, Urbaszek, Bernhard, Marie, Xavier, & Dey, Prasenjit. Gate-Controlled Spin-Valley Locking of Resident Carriers in WSe2 Monolayers. United States. doi:10.1103/PhysRevLett.119.137401.
Crooker, Scott A., Yang, Luyi, Robert, Cedric, Wang, Gang, Urbaszek, Bernhard, Marie, Xavier, and Dey, Prasenjit. 2017. "Gate-Controlled Spin-Valley Locking of Resident Carriers in WSe2 Monolayers". United States. doi:10.1103/PhysRevLett.119.137401. https://www.osti.gov/servlets/purl/1471348.
@article{osti_1471348,
title = {Gate-Controlled Spin-Valley Locking of Resident Carriers in WSe2 Monolayers},
author = {Crooker, Scott A. and Yang, Luyi and Robert, Cedric and Wang, Gang and Urbaszek, Bernhard and Marie, Xavier and Dey, Prasenjit},
abstractNote = {Using time-resolved Kerr rotation, we measure the spin-valley dynamics of resident electrons and holes in single charge-tunable monolayers of the archetypal transition-metal dichalcogenide (TMD) semiconductor WSe2. In the n-type regime, we observe long (~ 130 ns) polarization relaxation of electrons that is sensitive to in-plane magnetic fields By, indicating spin relaxation. In marked contrast, extraordinarily long (~ 2 μs) polarization relaxation of holes is revealed in the p-type regime, which is unaffected by By, directly confirming long-standing expectations of strong spin-valley locking of holes in the valence band of monolayer TMDs. Finally, supported by continuous-wave Kerr spectroscopy and Hanle measurements, these studies provide a unified picture of carrier polarization dynamics in monolayer TMDs, which can guide design principles for future valleytronic devices.},
doi = {10.1103/PhysRevLett.119.137401},
journal = {Physical Review Letters},
number = 13,
volume = 119,
place = {United States},
year = {2017},
month = {9}
}

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