Fig. 4
From: Parity transitions in the superconducting ground state of hybrid InSb–Al Coulomb islands
Evolution of multiple subgap states. a Schematic B-field dependence for the case of three subgap states with GS parity transitions at each zero-energy crossing. Dashed lines indicate level repulsion between different subgap states, leading to large oscillations of the lowest energy E0. b One example of Coulomb peaks reflected by the scenario in panel a. The extracted peak spacings for the valleys labelled by e and o are shown below in c. The evolution of the peak spacings is compatible with the type of energy spectrum shown in a characterised by large oscillations of E0. Note that the odd-parity GS around ~0.2 T develops a full 2e-periodicity. (The spacings near ~0.6 T are absent because the exact peak positions are unclear.) d Another example of Coulomb oscillations with a pronounced B-field dependence. Extracted peak spacings and the height ratio are shown in e (averaged over the three periods in d). f Coulomb diamonds at B∥ = 0.7 T along the VPG-range indicated by the yellow line in d. This bias spectroscopy reveals isolated zero-bias peaks at the charge-degeneracy points that are separated from the continuum. As in Fig. 2c, neighbouring zero-bias peaks have different heights (also visible in d at high B∥). g Bias spectroscopy with Al in the normal state (B⊥ = 0.3 T) where the isolated zero-bias peaks are absent
