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...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.展开更多
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).
文摘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.
