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

Nianze Shang ¹Chen Huang ²Qing Chen ³Chang Liu ²Guangjie Yao ²Zhipei Sun ⁴Sheng Meng ³Kaihui Liu ⁵Hao Hong⁶

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作者信息

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

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 twistron-ics systems.

Key words

Twisted bilayer graphene/van Hove singularity/Ultrafast photoluminescence/Hot carrier dynamics

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基金项目

National Key R&D Program of China(2021YFA1400201)

National Key R&D Program of China(2022YFA1403504)

National Key R&D Program of China(2021YFB3200303)

National Key R&D Program of China(2021YFA1400502)

National Natural Science Foundation of China(T2188101)

National Natural Science Foundation of China(52025023)

National Natural Science Foundation of China(51991342)

National Natural Science Foundation of China(52021006)

National Natural Science Foundation of China(92163206)

National Natural Science Foundation of China(11888101)

National Natural Science Foundation of China(12374167)

Guangdong Major Project of Basic and Applied Basic Research(2021B0301030002)

Strategic Priority Research Program of Chinese Academy of Sciences(XDB33000000)

Pearl River Talent Recruitment Program of Guangdong Province(2019ZT08C321)

New Cornerstone Science Foundation through the XPLORER PRIZE()

出版年

2024

科学通报(英文版)

中国科学院

科学通报(英文版)

CSTPCD

ISSN：1001-6538

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