Fig. 2: Tunneling spectra with a V-shape.
From: Single particle tunneling spectrum of superconducting Nd1-xSrxNiO2 thin films
a A tunneling spectrum with a V-shape (black circles), which is measured at the surface with large roughness after post-annealing. The Dynes model fitting (red solid curve) yields a gap function Δ = 3.9cos2θ (meV). b A typical V-shape spectrum (black circles) measured at the surface with much smaller roughness after a long time vacuum annealing. A gap function Δ = 3.95(0.95cos2θ + 0.05cos6θ) (meV) is used in the fitting (red solid curve). c Topographic image with much smaller roughness. Scale bar = 2 nm. d Five spectra measured on the five spots shown in c. Setting condition for a is Vbias = 10 mV, It = 100 pA, for b, d is Vbias = 4 mV, It = 100 pA and for c is Vbias = 0.36 V, It = 50 pA.
