Spin-degeneracy breaking and parity transitions in three-terminal Josephson junctions

Abstract

Harnessing spin and parity degrees of freedom is of fundamental importance for the realization of emergent quantum devices. Nanostructures embedded in superconductor--semiconductor hybrid materials offer novel and yet unexplored routes for addressing and manipulating fermionic modes. Here we spectroscopically probe the two-dimensional band structure of Andreev bound states in a phase-controlled hybrid three-terminal Josephson junction. Andreev bands reveal spin-degeneracy breaking, with level splitting in excess of 9 GHz, and zero-energy crossings associated to ground state fermion parity transitions, in agreement with theoretical predictions. Both effects occur without the need of external magnetic fields or sizable charging energies and are tuned locally by controlling superconducting phase differences. Our results highlight the potential of multiterminal hybrid devices for engineering quantum states.

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Cited by in corpus (10)

• Non-hermitian topology in multiterminal superconducting junctions
• Supercurrent through an Andreev trimer
• Flux-tunable Josephson Effect in a Four-Terminal Junction
• Mapping the topological proximity-induced gap of multiterminal Josephson junctions
• Phase-controlled minimal Kitaev chain in multiterminal Josephson junctions
• Exploring the energy spectrum of a four-terminal Josephson junction: Towards topological Andreev band structures
• Nonequilibrium Andreev resonances in ballistic graphene Andreev interferometers
• Revisiting the adiabatic limit in ballistic multiterminal Josephson junctions
• Spin splitting, Kondo correlation and singlet-doublet quantum phase transition in a superconductor-coupled InSb nanosheet quantum dot
• Impact of Layer Structure and Strain on Morphology and Electronic Properties of InAs Quantum Wells on InP (001)