Relativistic Artificial Molecules Realized by Two Coupled Graphene Quantum Dots

Zhong Qiu Fu, Yueting Pan, Jiao Jiao Zhou, Ke Ke Bai, Dong Lin Ma, Yu Zhang, Jia Bin Qiao, Hua Jiang*, Haiwen Liu*, Lin He*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)

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.

Original languageEnglish
Pages (from-to)6738-6743
Number of pages6
JournalNano Letters
Volume20
Issue number9
DOIs
Publication statusPublished - 9 Sept 2020
Externally publishedYes

Keywords

  • Klein tunneling
  • artificial molecules
  • graphene
  • quantum dot
  • scanning tunneling microscopy (STM) and spectroscopy (STS)

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