Real- and momentum-indirect neutral and charged excitons in a multi-valley semiconductor  

作　　者：Zhiheng Huang Yuhui Li Tao Bo Yanchong Zhao Fanfan Wu Lu Li Yalong Yuan Yiru Ji Le Liu Jinpeng Tian Yanbang Chu Xiaozhou Zan Yalin Peng Xiuzhen Li Yangkun Zhang Kenji Watanabe Takashi Taniguchi Zhipei Sun Wei Yang Dongxia Shi Shixuan Du Luojun Du Guangyu Zhang 

机构地区：[1]Beijing National Laboratory for Condensed Matter Physics,Key Laboratory for Nanoscale Physics and Devices,Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China [2]School of Physical Sciences,University of Chinese Academy of Sciences,Beijing 100190,China [3]Ningbo Institute of Materials Technology&Engineering,Chinese Academy of Sciences,Ningbo 315201,China [4]Research Center for Functional Materials,National Institute for Materials Science,1-1 Namiki,Tsukuba 305-0044,Japan [5]International Center for Materials Nanoarchitectonics,National Institute for Materials Science,1-1 Namiki,Tsukuba 305-0044,Japan [6]Department of Electronics and Nanoengineering,Aalto University,Tietotie 3,Espoo FI-02150,Finland [7]Quantum Technology Finland(QTF)Centre of Excellence,Department of Applied Physics,Aalto University,Aalto FI-00076,Finland [8]Beijing Key Laboratory for Nanomaterials and Nanodevices,Beijing 100190,China [9]Songshan Lake Materials Laboratory,Dongguan 523808,China

出　　处：《National Science Open》2023年第4期76-85,共10页国家科学进展（英文）

基　　金：This work was supported by the National Natural Science Foundation of China(NSFC)(12274447,61888102,11834017,61734001,and 12074412);the National Key Research and Development Program(2021YFA1202900 and 2021YFA1400502);the Strategic Priority Research Program of Chinese Academy of Sciences(XDB30000000);the Key-Area Research and Development Program of Guangdong Province(2020B0101340001).

摘　　要：Excitons dominate the photonic and optoelectronic properties of a material.Although significant advancements exist in understanding various types of excitons,progress on excitons that are indirect in both real-and momentum-spaces is still limited.Here,we demonstrate the real-and momentum-indirect neutral and charged excitons(including their phonon replicas)in a multi-valley semiconductor of bilayer MoS_(2),by performing electric-field/doping-density dependent photoluminescence.Together with first-principles calculations,we uncover that the observed real-and momentum-indirect exciton involves electron/hole from K/Γvalley,solving the longstanding controversy of its momentum origin.Remarkably,the binding energy of real-and momentum-indirect charged exciton is extremely large(i.e.,~59 meV),more than twice that of real-and momentum-direct charged exciton(i.e.,~24 meV).The giant binding energy,along with the electrical tunability and long lifetime,endows real-and momentum-indirect excitons an emerging platform to study many-body physics and to illuminate developments in photonics and optoelectronics.

关 键 词：excitons real-and momentum-indirect exciton giant binding energy electrical tunability multi-valley semiconductor 

分 类 号：O471[理学—半导体物理]