中国物理B ›› 2010, Vol. 19 ›› Issue (6): 67401-067401.doi: 10.1088/1674-1056/19/6/067401

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Phase escape of current-biased Josephson junctions

曹文会, 于海峰, 田野, 陈赓华, 赵士平   

  1. Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
  • 收稿日期:2009-11-25 出版日期:2010-06-15 发布日期:2010-06-15
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos.~10534060 and 10874231) and National Basic Research Program of China (Grant Nos.~2006CB601007, 2006CB921107, and 2009CB929102).

Phase escape of current-biased Josephson junctions

Cao Wen-Hui(曹文会), Yu Hai-Feng(于海峰), Tian Ye(田野), Chen Geng-Hua(陈赓华), and Zhao Shi-Ping(赵士平)†   

  1. Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
  • Received:2009-11-25 Online:2010-06-15 Published:2010-06-15
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos.~10534060 and 10874231) and National Basic Research Program of China (Grant Nos.~2006CB601007, 2006CB921107, and 2009CB929102).

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摘要： Switching current distributions of an Nb/Al--AlO_x/Nb Josephson junction are measured in a temperature range from 25~mK to 800~mK. We analyse the phase escape properties by using the theory of Larkin and Ovchinnikov (LO) which takes discrete energy levels into account. Our results show that the phase escape can be well described by the LO approach for temperatures near and below the crossover from thermal activation to macroscopic quantum tunneling. These results are helpful for further study of macroscopic quantum phenomena in Josephson junctions where discrete energy levels need to be considered.

Abstract: Switching current distributions of an Nb/Al--AlOx/Nb Josephson junction are measured in a temperature range from 25 mK to 800 mK. We analyse the phase escape properties by using the theory of Larkin and Ovchinnikov (LO) which takes discrete energy levels into account. Our results show that the phase escape can be well described by the LO approach for temperatures near and below the crossover from thermal activation to macroscopic quantum tunneling. These results are helpful for further study of macroscopic quantum phenomena in Josephson junctions where discrete energy levels need to be considered.

Key words: Nb junctions, phase escapes, macroscopic quantum phenomena, discrete energy levels

中图分类号:  (Tunneling phenomena; Josephson effects)

  • 74.50.+r
74.20.-z (Theories and models of superconducting state)