Probing Superconducting Phase Fluctuations from the Current Noise Spectrum of Pseudogapped Metal-Superconductor Tunnel Junctions

Xi Dai, Tao Xiang, Tai-Kai Ng, Zhao-bin Su
2000 Physical Review Letters  
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 tunnelling current noise shows a series of characteristic peaks with increasing DC voltage. Experimental observation of
more » ... ntal observation of these peaks will give direct evidence of the pair fluctuation in the normal state of high-$T_c$ superconductors and from the half width of the peaks the pair decay rate can be estimated.
doi:10.1103/physrevlett.85.3009 pmid:11005990 fatcat:lzxerjibh5htdhrtjr7sbzcota