Nonequilibrium interplay between Andreev bound states and Kondo effect

Abstract

Andreev bound states (ABSs), as a close resemblance and a prototype of Majorana bound states, attracted particular interest in semiconductor-superconductor hybrids. So far, ABSs were explored as an equilibrium behavior employing tunneling spectroscopy. Under nonequilibrium, theorists did predict that the local density of states (DOS) of the ABSs split and broaden. We investigated an InAsSb quantum dot coupled to two superconductors to explore the nonequilibrium dynamics of ABSs and their interplay with Kondo effect. Through tunneling spectroscopy, we demonstrated a full picture of the nonequilibrium dynamic splitting and broadening of ABSs, which interplays with the nonequilibrium Kondo DOS. Since the observed features might mimic those in the normal superconductor-topological superconductor or Majorana junctions, our discovery could provide a relevant comparison to benchmark the Majorana signal in future experiments.