中国物理B ›› 2022, Vol. 31 ›› Issue (3): 37401-037401.doi: 10.1088/1674-1056/ac1b8e

• • 上一篇    下一篇

Electronic properties and interfacial coupling in Pb islands on single-crystalline graphene

Jing-Peng Song(宋靖鹏)1,2 and Ang Li(李昂)1,2,†   

  1. 1 State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China;
    2 University of Chinese Academy of Sciences, Beijing 100049, China
  • 收稿日期:2021-06-22 修回日期:2021-07-26 接受日期:2021-08-07 出版日期:2022-02-22 发布日期:2022-02-24
  • 通讯作者: Ang Li E-mail:angli@mail.sim.ac.cn
  • 基金资助:
    Project supported by the Science Foundation of the Science and Technology Commission of Shanghai Municipality, China (Grant No. 18ZR1447300).

Electronic properties and interfacial coupling in Pb islands on single-crystalline graphene

Jing-Peng Song(宋靖鹏)1,2 and Ang Li(李昂)1,2,†   

  1. 1 State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China;
    2 University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2021-06-22 Revised:2021-07-26 Accepted:2021-08-07 Online:2022-02-22 Published:2022-02-24
  • Contact: Ang Li E-mail:angli@mail.sim.ac.cn
  • Supported by:
    Project supported by the Science Foundation of the Science and Technology Commission of Shanghai Municipality, China (Grant No. 18ZR1447300).

RichHTML

0

PDF (PC)

63

赞

摘要： Introducing metal thin films on two-dimensional (2D) material may present a system to possess exotic properties due to reduced dimensionality and interfacial effects. We deposit Pb islands on single-crystalline graphene on a Ge(110) substrate and studied the nano- and atomic-scale structures and low-energy electronic excitations with scanning tunneling microscopy/spectroscopy (STM/STS). Robust quantum well states (QWSs) are observed in Pb(111) islands and their oscillation with film thickness reveals the isolation of free electrons in Pb from the graphene substrate. The spectroscopic characteristics of QWSs are consistent with the band structure of a free-standing Pb(111) film. The weak interface coupling is further evidenced by the absence of superconductivity in graphene in close proximity to the superconducting Pb islands. Accordingly, the Pb(111) islands on graphene/Ge(110) are free-standing in nature, showing very weak electronic coupling to the substrate.

关键词: scanning tunneling microscopy, graphene, quantum well states, superconducting proximity effect

Abstract: Introducing metal thin films on two-dimensional (2D) material may present a system to possess exotic properties due to reduced dimensionality and interfacial effects. We deposit Pb islands on single-crystalline graphene on a Ge(110) substrate and studied the nano- and atomic-scale structures and low-energy electronic excitations with scanning tunneling microscopy/spectroscopy (STM/STS). Robust quantum well states (QWSs) are observed in Pb(111) islands and their oscillation with film thickness reveals the isolation of free electrons in Pb from the graphene substrate. The spectroscopic characteristics of QWSs are consistent with the band structure of a free-standing Pb(111) film. The weak interface coupling is further evidenced by the absence of superconductivity in graphene in close proximity to the superconducting Pb islands. Accordingly, the Pb(111) islands on graphene/Ge(110) are free-standing in nature, showing very weak electronic coupling to the substrate.

Key words: scanning tunneling microscopy, graphene, quantum well states, superconducting proximity effect

中图分类号:  (Tunneling phenomena: single particle tunneling and STM)

  • 74.55.+v
68.65.-k (Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties) 74.78.-w (Superconducting films and low-dimensional structures) 74.45.+c (Proximity effects; Andreev reflection; SN and SNS junctions)