Switching current of a Cooper pair transistor with tunable Josephson junctions
Abstract
We investigate the switching current of a Cooper pair transistor with tunable Josephson energy. The junctions are fabricated in a superconducting quantum interference device (SQUID) geometry which allows for an in situ tunable effective Josephson energy by application of a magnetic field. We find a 2eperiodic switching current versus gate charge. As the magnetic field is increased the switching current stays 2eperiodic but the magnitude is suppressed. At a magnetic field of half a flux quantum through the SQUID's the switching current is minimum. We can theoretically model the experimental data by assuming a switching current which is proportional to the ideal critical current squarred. We show that such a dependence is expected in the limit where the effect of thermal fluctuations on the system is strong.
 Publication:

Physical Review B
 Pub Date:
 June 2002
 DOI:
 10.1103/PhysRevB.66.014510
 Bibcode:
 2002PhRvB..66a4510A
 Keywords:

 74.50.+r;
 73.40.Gk;
 73.40.Rw;
 Tunneling phenomena;
 point contacts weak links Josephson effects;
 Tunneling;
 Metalinsulatormetal structures