Open AccessHigh room temperature optical polarization due to spin-valley coupling in monolayer WS2
Author(s) -
A. T. Hanbicki,
Kathleen M. McCreary,
Γ. Κιοσέογλου,
Marc Currie,
C. Stephen Hellberg,
Adam L. Friedman,
Berend T. Jonker
Publication year - 2016
Publication title -
aip advances
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.421
H-Index - 58
ISSN - 2158-3226
DOI - 10.1063/1.4942797
Subject(s) - trion , exciton , photoluminescence , polarization (electrochemistry) , atomic physics , electron , materials science , scattering , monolayer , spin polarization , condensed matter physics , optoelectronics , physics , chemistry , optics , nanotechnology , quantum mechanics
We prepare single-layer WS2 films such that the photoluminescence is from either the neutral exciton or the negatively charged trion. While the neutral exciton emission has zero polarization at room temperature, we observe a room temperature optical polarization in excess of 40% for the trion. Using an applied gate voltage, we can modulate the electron density, and subsequently the polarization of the trion emission continuously from 20-40%. Both the polarization and the emission energy monotonically track the gate voltage with the emission energy increasing by 45 meV. We discuss the role electron capture by the exciton has on suppressing the intervalley scattering process
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