Fig. 3: Scaling of conductance quantization with bilayer coupling.

a, b Low bias differential conductance plots for nanowires of length a 2.25 μm, and b 4.5 μm in the topological region (External Zeeman field, \({V}_{Z}^{ext}=0.07{\Delta }_{0}\)) (orange) and trivial region (\({V}_{Z}^{ext}=0.005{\Delta }_{0}\)) (green). The topological regime shows clear conductance peaks absent in the trivial regime, though not quantized. The splitting of the zero bias peak is more pronounced for the shorter nanowire, consistent with Fig. 2. c Shows that as the coupling to the normal contacts, γ, is increased, so that it becomes much larger than the coupling, γ_SC, between the nanowire and the superconductor-magnetic insulator bilayer, the peak asymptotically reaches the expected quantized value. The bare superconducting gap in the parent superconductor Δ₀ sets the scale for all energies. The differential conductance, G is plotted as a function of the bias, V. G is measured in units of e²/h, which is the conductance quantum, e being the electronic charge and h being Planck’s constant.