Figure 4: Theoretical fitting results by two isotropic s -wave gaps.

The fitting results shown as solid lines with different fitting parameters fail to catch up the main features of the experimental data. For the fittings, Δ₁=13 meV and Δ₂=8.5 meV, Γ₁=Γ₂=0.15 meV were used for the clean case (red line), while the same gaps and Γ₁=1.2 and Γ₂=0.85 meV for the case of finite scattering rates (blue one). From these fittings, one can see that the tunnelling spectrum cannot be fitted with two isotropic gaps.