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Fu ZQ, Pan Y, Zhou JJ, Bai KK, Ma DL, Zhang Y, Qiao JB, Jiang H, Liu H, He L. Relativistic Artificial Molecules Realized by Two Coupled Graphene Quantum Dots. NANO LETTERS 2020; 20:6738-6743. [PMID: 32787177 DOI: 10.1021/acs.nanolett.0c02623] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Coupled quantum dots (QDs), usually referred to as artificial molecules, are important not only in exploring fundamental physics of coupled quantum objects but also in realizing advanced QD devices. However, previous studies have been limited to artificial molecules with nonrelativistic Fermions. Here, we show that relativistic artificial molecules can be realized when two circular graphene QDs are coupled to each other. Using scanning tunneling microscopy (STM) and spectroscopy (STS), we observe the formation of bonding and antibonding states of the relativistic artificial molecule and directly visualize these states of the two coupled graphene QDs. The formation of the relativistic molecular states strongly alters distributions of massless Dirac Fermions confined in the graphene QDs. Moreover, our experiment demonstrates that the degeneracy of different angular-momentum states in the relativistic artificial molecule can be further lifted by external magnetic fields. Then, both the bonding and antibonding states are split into two peaks.
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Affiliation(s)
- Zhong-Qiu Fu
- Center for Advanced Quantum Studies, Department of Physics, Beijing Normal University, Beijing 100875, People's Republic of China
| | - Yueting Pan
- Center for Advanced Quantum Studies, Department of Physics, Beijing Normal University, Beijing 100875, People's Republic of China
| | - Jiao-Jiao Zhou
- College of Physics, Optoelectronics and Energy and Institute for Advanced Study, Soochow University, Suzhou 215006, People's Republic of China
| | - Ke-Ke Bai
- Center for Advanced Quantum Studies, Department of Physics, Beijing Normal University, Beijing 100875, People's Republic of China
- Institute of Physics, Hebei Normal University, Shijiazhuang 050024, People's Republic of China
| | - Dong-Lin Ma
- Center for Advanced Quantum Studies, Department of Physics, Beijing Normal University, Beijing 100875, People's Republic of China
- Department of Physics, Capital Normal University, Beijing 100048, People's Republic of China
| | - Yu Zhang
- Center for Advanced Quantum Studies, Department of Physics, Beijing Normal University, Beijing 100875, People's Republic of China
| | - Jia-Bin Qiao
- Center for Advanced Quantum Studies, Department of Physics, Beijing Normal University, Beijing 100875, People's Republic of China
| | - Hua Jiang
- College of Physics, Optoelectronics and Energy and Institute for Advanced Study, Soochow University, Suzhou 215006, People's Republic of China
| | - Haiwen Liu
- Center for Advanced Quantum Studies, Department of Physics, Beijing Normal University, Beijing 100875, People's Republic of China
| | - Lin He
- Center for Advanced Quantum Studies, Department of Physics, Beijing Normal University, Beijing 100875, People's Republic of China
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Site control of InAs quantum dots on GaAs surfaces patterned by in situ electron-beam lithography. ACTA ACUST UNITED AC 2000. [DOI: 10.1116/1.1322039] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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