Tunneling spectroscopy of multi-phase-dependent Andreev bound states in three-terminal Josephson junctions

A Josephson junction (JJ) hosts localized subgap excitations called Andreev bound states (ABSs) whose energies depend on the superconducting phase difference across the junction. When more than two superconductors form a “multi-terminal” JJ, multiple independent phase differences are defined across the junction and its ABSs may depend on those multiple phases. In this talk, we will discuss the energy spectrum of the multi-phase-dependent ABSs in three-terminal JJs obtained by tunneling spectroscopy measurements. Since the ABS energy spectrum mimics electronic band structure in solid, multi-terminal JJs provide a new platform to study band topology in higher dimensional parameter space.