Resistance fluctuations near the Berezinskii-Kosterlitz-Thouless transition temperature in low dimensional superconductors

摘要

We have studied resistance fluctuations in two different types of two-dimensional superconductors near to the Bcrczinskii-Kostcrlitz-Thoulcss (BKT) transition. The power spectral density of the resistance fluctuations was seen to deviate from 1/f as transition temperature is approached. We find that the shape of the spectrum can not be explained by a model for local defect fluctuations. Probability distribution function(PDF) and voltage-voltage auto-correlation functions provides evidence of the non-Gaussian nature of the resistance fluctuations near the BKT transition.