Bias-induced local heating in Au atom-sized contacts

Bias-induced local heating in Au atom-sized contacts (ASCs) has been studied at 4.2 K by measuring the frequency ν of the conductance two-level fluctuations (TLFs) under high biases of 0.60–0.95 V. The measured logν shows a broad single-peak distribution with the peak frequency logν m shifting to higher values with increasing bias. The logν m –V plot is nonlinear at 4.2 K in contrast to the linear behaviour observed at 77 K. The difference in the bias dependence of logν m manifests a bias-induced overheating in Au ASCs at 4.2 K, which renders the effective contact temperature T eff much higher than 4.2 K. Our experimental results suggest that .