Figure 8.

Measurements on sample NbN80/1. (a) $R\left(T\right)$. Inset: the same data on an expanded scale showing the low-temperature region. (b) High-bias $I\left(V\right)$ at 330 mK. (c) $I\left(V\right)$ at three temperatures above and below $T_{\mathrm{c}}$, 350 mK, 1.92 K and 12.98 K. In all sub-plots, lines join consecutive data points. Voltage- and current-offsets of −1.25 mV, 0.5 mV and −0.28 mV and 5.5 pA, 6.0 pA and 5.5 pA, respectively, have been subtracted from the respective datasets in (c). The slight hysteresis observed in the measurement at 12.98 K is not a property of the sample, but rather an artefact associated with carrying out the measurement relatively rapidly (see Section 3.2).