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...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.展开更多
基金supported by the National Key R&D Program of China(2021YFA1400201,2022YFA1403504,2021YFB32003032021YFA1400502)+4 种基金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。
文摘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.
基金supported by the National Natural Science Foundation of China (61825401 and 91964201)the Innovation Program for Quantum Science and Technology (2021ZD0302403)。
