中国物理B ›› 2019, Vol. 28 ›› Issue (9): 97401-097401.doi: 10.1088/1674-1056/ab33f4

• CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES • 上一篇    下一篇

Josephson effect in the strontium titanate/lanthanum aluminate junction

Xing Yang(阳星), Jie Chen(陈杰), Yabin Yu(余亚斌), Quanhui Liu(刘全慧)   

  1. School of Physics and Electronics, Hunan University, Changsha 410082, China
  • 收稿日期:2019-02-28 修回日期:2019-06-26 出版日期:2019-09-05 发布日期:2019-09-05
  • 通讯作者: Xing Yang E-mail:yangxing@hnu.edu.cn
  • 基金资助:

    Project supported by the National Natural Science Foundation of China (Grant No. 11675051) and China Scholarship Council (Grant No. 201506130054).

Josephson effect in the strontium titanate/lanthanum aluminate junction

Xing Yang(阳星), Jie Chen(陈杰), Yabin Yu(余亚斌), Quanhui Liu(刘全慧)   

  1. School of Physics and Electronics, Hunan University, Changsha 410082, China
  • Received:2019-02-28 Revised:2019-06-26 Online:2019-09-05 Published:2019-09-05
  • Contact: Xing Yang E-mail:yangxing@hnu.edu.cn
  • Supported by:

    Project supported by the National Natural Science Foundation of China (Grant No. 11675051) and China Scholarship Council (Grant No. 201506130054).

摘要:

We report theoretical studies on the newly discovered novel Josephson effect and scanning tunneling spectroscopy (STS) at the interface of strontium titanate/lanthanum aluminate (STO/LAO). With a phenomenological boson-fermion model, the density of states is calculated and the results are consistent with the STS experiments. A typical calculation of Josephson effect is performed, and it is in qualitative agreement with the experiments. The calculations indicate that the gap states come from the pairing of quasi-particles with a finite total momentum and the Josephson current comes from the tunneling of quasi-particle pairs with zero momentum. The quasi-particles are Bogoliubov quasi-particles. Moreover, the fits using Kulik's formula imply that the Josephson junction at the STO/LAO interface has a point contact with the clean superconductor limit.

关键词: strontium titanate/lanthanum aluminate, Josephson effect, scanning tunneling spectroscopy, pseudogap

Abstract:

We report theoretical studies on the newly discovered novel Josephson effect and scanning tunneling spectroscopy (STS) at the interface of strontium titanate/lanthanum aluminate (STO/LAO). With a phenomenological boson-fermion model, the density of states is calculated and the results are consistent with the STS experiments. A typical calculation of Josephson effect is performed, and it is in qualitative agreement with the experiments. The calculations indicate that the gap states come from the pairing of quasi-particles with a finite total momentum and the Josephson current comes from the tunneling of quasi-particle pairs with zero momentum. The quasi-particles are Bogoliubov quasi-particles. Moreover, the fits using Kulik's formula imply that the Josephson junction at the STO/LAO interface has a point contact with the clean superconductor limit.

Key words: strontium titanate/lanthanum aluminate, Josephson effect, scanning tunneling spectroscopy, pseudogap

中图分类号:  (Theories and models of superconducting state)

  • 74.20.-z
74.25.F- (Transport properties) 74.50.+r (Tunneling phenomena; Josephson effects)