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Title:DIRECT DETERMINATION OF MOMENTUM-RESOLVED ELECTRON TRANSFER IN PHOTOEXCITED MoS2/WS2 VAN DER WAALS HETEROBILAYER
Author(s):Liu, Fang
Contributor(s):Zhu, Xiaoyang ; Li, Qiuyang
Subject(s):Plenary
Abstract:Photo-induced charge separation in transition metal dichalcogenide heterobilayers is being explored for moir\'{e} excitons, spin-valley polarization, and quantum phases of excitons/electrons. While different momentum spaces may be critically involved in charge separation dynamics, little is known directly from experiments. Here we determine momentum-resolved electron dynamics in the \chem{WS_2/MoS_2} heterobilayer using time and angle resolved photoemission spectroscopy (TR-ARPES). Upon photoexcitation in the K valleys, we detect electrons in M/2, M, and Q valleys/points on time scales as short as $\sim$70 fs, followed by dynamic equilibration in K and Q valleys in $\sim$400 fs. The interlayer charge transfer is accompanied by momentum-specific band renormalization. These findings reveal the essential role of phonon scattering, the coexistence of direct and indirect interlayer excitons, and constraints on spin-valley polarization.
Issue Date:25-Jun-20
Publisher:International Symposium on Molecular Spectroscopy
Citation Info:APS
Genre:CONFERENCE PAPER/PRESENTATION
Type:Text
Language:English
URI:http://hdl.handle.net/2142/107348
Date Available in IDEALS:2020-06-26


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