Superior valley polarization and coherence of 2s excitons in monolayer WSe<sub>2</sub>
ORAL
Abstract
We report on the fabrication and spectroscopic measurement of high-quality monolayer WSe2 crystals. The excitonic emission features in these samples exhibit narrow linewidth. We fully resolve the exchange-interaction-split trion doublet at low temperatures and observe the 2s exciton luminescence up to room temperature. From comparison with absorption spectra, both 1s and 2s luminescence radiation exhibit near-zero Stokes shift, confirming that disorders in these samples are minimal. Remarkably, under similar experimental conditions, the 2s luminescence is found to exhibit much better valley polarization and coherence than 1s. We explain our experimental results in the framework of exchange interaction induced intervalley scattering, the Maialle-Silva-Sham mechanism.
*This work is supported mainly by the University of Massachusetts Amherst and in part by NSF ECCS-1509599. T.T. and K.W. acknowledge support from the Elemental Strategy Initiative conducted by the MEXT, Japan and JSPS KAKENHI Grant Numbers JP26248061, JP15K21722 and JP25106006.
–
Presenters
Jun Yan
Physics, Univ of Mass - Amherst
Univ of Mass - Amherst
Authors
Jun Yan
Physics, Univ of Mass - Amherst
Univ of Mass - Amherst
Shao-Yu Chen
Physics, Univ of Mass - Amherst
Thomas Goldstein
Physics, Univ of Mass - Amherst
Takashi Taniguchi
National Institute for Materials Science
NIMS
National Institute for Material Science
Advanced Materials Laboratory, National Institute for Materials Science
National Institute of Materials Science
Research Center for Functional Materials, National Institute for Materials Science
National Institute for Materials Science (NIMS
Advanced Materials Laboratory, NIMS
National Institute for Materials Science, Advanced Materials Laboratory
National Institue for Materials Science
National Institute of Material Science
National Institute for Matericals Science
Advanced Materials Laboratory
National Institute for Materials Science, 1-1 Namiki
NIMS-Japan
Kenji Watanabe
National Institute for Materials Science
NIMS
National Institute for Material Science
Advanced Materials Laboratory, National Institute for Materials Science
National Institute of Materials Science
Research Center for Functional Materials, National Institute for Materials Science
National Institute for Materials Science (NIMS
Advanced Materials Laboratory, NIMS
National Institute for Materials Science, Advanced Materials Laboratory
National Institue for Materials Science
National Institute of Material Science
National Institute for Matericals Science
Advanced Materials Laboratory
National Institute for Materials Science, 1-1 Namiki
Advanced materials laboratory, National institute for Materials Science
