Evidence of abnormal hot carrier thermalization at van Hove singularity of twisted bilayer graphene  

转角双层石墨烯范霍夫奇点热载流子反常热化的证据

作　　者：Nianze Shang Chen Huang Qing Chen Chang Liu Guangjie Yao Zhipei Sun Sheng Meng Kaihui Liu Hao Hong 尚念泽;黄琛;陈擎;刘畅;姚光杰;孙志培;孟胜;刘开辉;洪浩

机构地区：[1]State Key Laboratory for Mesoscopic Physics,Frontiers Science Center for Nano-optoelectronics,School of Physics,Peking University,Beijing 100871,China [2]QTF Centre of Excellence,Department of Electronics and Nanoengineering,Aalto University,Espoo 02150,Finland [3]Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China [4]Songshan Lake Materials Lab,Institute of Physics,Chinese Academy of Sciences,Dongguan 523808,China [5]Interdisciplinary Institute of Light-Element Quantum Materials and Research Centre for Light-Element Advanced Materials,Peking University,Beijing 100871,China

出　　处：《Science Bulletin》2024年第16期2522-2528,共7页科学通报（英文版）

基　　金：supported by the National Key R&D Program of China(2021YFA1400201,2022YFA1403504,2021YFB3200303;2021YFA1400502);the National Natural Science Foundation of China(T2188101,52025023,51991342,52021006,92163206,11888101,and 12374167);Guangdong Major Project of Basic and Applied Basic Research(2021B0301030002);the Strategic Priority Research Program of Chinese Academy of Sciences(XDB33000000);the Pearl River Talent Recruitment Program of Guangdong Province(2019ZT08C321);the New Cornerstone Science Foundation through the XPLORER PRIZE。

摘　　要：Interlayer twist evokes revolutionary changes to the optical and electronic properties of twisted bilayer graphene(TBG)for electronics,photonics and optoelectronics.Although the ground state responses in TBG have been vastly and clearly studied,the dynamic process of its photoexcited carrier states mainly remains elusive.Here,we unveil the photoexcited hot carrier dynamics in TBG by time-resolved ultrafast photoluminescence(PL)autocorrelation spectroscopy.We demonstrate the unconventional ultrafast PL emission between the van Hove singularities(VHSs)with a~4 times prolonged relaxation lifetime.This intriguing photoexcited carrier behavior is ascribed to the abnormal hot carrier thermalization brought by bottleneck effects at VHSs and interlayer charge distribution process.Our study on hot carrier dynamics in TBG offers new insights into the excited states and correlated physics of graphene twistronics systems.

关 键 词：Twisted bilayer graphene van Hove singularity Ultrafast photoluminescence Hot carrier dynamics 

分 类 号：TQ127.11[化学工程—无机化工]