Probing superconducting phase fluctuations from the current noise spectrum of pseudogapped metal-superconductor tunnel junctions.
We study the current noise spectra of a tunnel junction of a metal with strong pairing phase fluctuation and a superconductor. It is shown that there is a characteristic peak in the noise spectrum at the intrinsic Josephson frequency omega(J) = 2eV when omega(J) is smaller than the pairing gap but larger than the pairing scattering rate. In the presence of an ac voltage, the tunneling current noise shows a series of characteristic peaks with increasing dc voltage. Experimental observation of these peaks will give direct evidence of the pair fluctuation in the normal state of high- T(c) superconductors and the pair decay rate can be estimated from the half width of the peaks.
Dai
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Physics Department, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong.
Xiang
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T
Ng
T K
TK
Su
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