Mesoscopic Fluctuations of the DC Josephson Current in a Dirty SNS Junction

概要

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We present theoretical studies on naesoscopic Iltrctuations of the dc Josephson current in supercondtrctor (S)-dirty normal condtrctor (N)-superconductor .junctions. The analytical expressionfor the Josephson-current flucttration l5J' is obt?rined by using the thermal Green's f'unctionnnethod, which is shown to be valid when the separatiota between two strpercondttctors is nauchlager than the coherence length of the dirty strpercondtrctor. The effects of tenaperattrre andinelastic scattering on 6J' are exanaitaed. The resttlts show that the characteristic tetnperattrre(size) for the redtrction of 61' is of the order of the Thouless correlation energy E. (the phasechoherence length). Frotn the cvrrrent correlation function, the energy correlation range is es-tinaated to be at abotrt E.. In order to prep?rre a specific reference for the systern trnder OLIIconsideration, we numerically examine the critical-cturrent fltrctuations 6J3 in the long-.junctionlimit in a taaodel system. Nurnerical restrlts show that the naagnittrde of 6J/ and energy cor-relation range agree with our analytical restrlt. The effect of the barrier potential at the NSinterfaces is ntrunerically investigated. XX7e find that the experitaaental result by Takatyanagi et at.can be explained qtmantitatively within the ['ranaework of otrr theory.
社団法人日本物理学会の論文
1997-02-15