Large Photoluminescence Enhancement by an Out-of-Plane Magnetic Field in Exfoliated WS2 Flakes  

作　　者：Sibai Sun Jianchen Dang Xin Xie Yang Yu Longlong Yang Shan Xiao Shiyao Wu Kai Peng Feilong Song Yunuan Wang Jingnan Yang Chenjiang Qian Zhanchun Zuo Xiulai Xu 孙思白;党剑臣;谢昕;于洋;杨龙龙;肖姗;武诗瑶;彭凯;宋飞龙;王玉暖;杨静南;钱琛江;左战春;许秀来(Beijing National Laboratory for Condensed Matter Physics,Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China;CAS Center for Excellence in Topological Quantum Computation and School of Physical Sciences,University of Chinese Academy of Sciences,Beijing 100049,China;Key Laboratory of Luminescence and Optical Information(Ministry of Education),Beijing Jiaotong University,Beijing 100044,China;Songshan Lake Materials Laboratory,Dongguan 523808,China)

机构地区：[1]Beijing National Laboratory for Condensed Matter Physics,Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China [2]CAS Center for Excellence in Topological Quantum Computation and School of Physical Sciences,University of Chinese Academy of Sciences,Beijing 100049,China [3]Key Laboratory of Luminescence and Optical Information(Ministry of Education),Beijing Jiaotong University,Beijing 100044,China [4]Songshan Lake Materials Laboratory,Dongguan 523808,China

出　　处：《Chinese Physics Letters》2020年第8期156-161,共6页中国物理快报（英文版）

基　　金：Supported by the National Natural Science Foundation of China(Grants Nos.11934019,61675228,11721404,51761145104 and 11874419);the Strategic Priority Research Program,the Instrument Developing Project and the Interdisciplinary Innovation Team of the Chinese Academy of Sciences(Grant Nos.XDB28000000 and YJKYYQ20180036);the Key Research and Development Program of Guangdong Province(Grant No.2018B030329001).

摘　　要：We report an out-of-plane magnetic field induced large photoluminescence enhancement in WS2 flakes at 4K,in contrast to the photoluminescence enhancement provided by an in-plane field in general.Two mechanisms for the enhancement are proposed.One is a larger overlap of the electron and hole caused by the magnetic field induced confinement.The other is that the energy difference between varLambda and K valleys is reduced by magnetic field,and thus enhancing the corresponding indirect-transition trions.Meanwhile,the Landé g factor of the trion is measured to be-0.8,whose absolute value is much smaller than normal exciton,which is around-4.A model for the trion gfactor is presented,confirming that the smaller absolute value of the Landé g factor is a behavior of this A–Ktrion.By extending the valley space,we believe this work provides a further understanding of the valleytronics in monolayer transition metal dichalcogenides.

关 键 词：WS2 VALLEY ABSOLUTE 

分 类 号：O482.55[理学—固体物理]