標題: Optically initialized robust valley-polarized holes in monolayer WSe2
作者: Hsu, Wei-Ting
Chen, Yen-Lun
Chen, Chiang-Hsiao
Liu, Pang-Shiuan
Hou, Tuo-Hung
Li, Lain-Jong
Chang, Wen-Hao
電子物理學系
電子工程學系及電子研究所
Department of Electrophysics
Department of Electronics Engineering and Institute of Electronics
公開日期: 1-Nov-2015
摘要: A robust valley polarization is a key prerequisite for exploiting valley pseudospin to carry information in next-generation electronics and optoelectronics. Although monolayer transition metal dichalcogenides with inherent spin-valley coupling offer a unique platform to develop such valleytronic devices, the anticipated long-lived valley pseudospin has not been observed yet. Here we demonstrate that robust valley-polarized holes in monolayer WSe2 can be initialized by optical pumping. Using time-resolved Kerr rotation spectroscopy, we observe a long-lived valley polarization for positive trion with a lifetime approaching 1 ns at low temperatures, which is much longer than the trion recombination lifetime (similar to 10-20 ps). The long-lived valley polarization arises from the transfer of valley pseudospin from photocarriers to resident holes in a specific valley. The optically initialized valley pseudospin of holes remains robust even at room temperature, which opens up the possibility to realize room-temperature valleytronics based on transition metal dichalcogenides.
URI: http://dx.doi.org/10.1038/ncomms9963
http://hdl.handle.net/11536/129394
ISSN: 2041-1723
DOI: 10.1038/ncomms9963
期刊: NATURE COMMUNICATIONS
Volume: 6
起始頁: 0
結束頁: 0
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