Effect of thermal phase fluctuations on the inductances of Josephson junctions, arrays of junctions, and superconducting films
نویسندگان
چکیده
We calculate the factor by which thermal phase fluctuations, as distinct from phase-slip fluctuations, increase the inductance LJ of a resistively shunted Josephson junction ~JJ! above its mean-field value L0 . We find that quantum mechanics suppresses fluctuations when T drops below a temperature, TQ5\/kBGL0 , where G is the shunt conductance. Examination of the calculated sheet inductance LA(T)/L0(T) of arrays of JJ’s reveals that two-dimensional ~2D! interconnections halve fluctuation effects, while reducing phase-slip effects by a much larger factor. Guided by these results, we calculate the sheet inductance LF(T)/L0(T) of 2D films by treating each plasma oscillation mode as an overdamped JJ. In disordered s-wave superconductors, quantum suppression is important for LF(0)/LF(T).0.14 ~or T/TC0,0.94!. In optimally doped YBCO and BSCCO quantum suppression is important for l(0)/l(T).0.25, where l is the penetration depth.
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