Fig. 4.

Transport characteristics of the strong tunneling regime. a Bias spectroscopy of the conductance G(V _g) in the strong coupling regime V _g>0.6 V for B=0, showing diamond-shaped regions of suppressed conductance. The zero-bias resonance at the gate voltage indicated by the white arrow is studied for varying in-plane magnetic field B _y b–d and temperature e, f with and without out-of-plane magnetic field $B_z>B_{\mathrm{c}}^z$ to suppress superconductivity in the leads. In e, f the arrows emphasize the temperature dependence of the peak conductance. g Extracted peak height from f, fitted to −log(T) (black line). h Extracted peak height from e with T _c of the leads (dashed line) found from independent measurements of the leads