Selective Control of Conductance Modes in Multi-terminal Josephson Junctions

TL;DR

This paper demonstrates independent control of conductance modes in three-terminal Josephson junctions using a quantum point contact, enabling access to single-mode regimes and paving the way for tunable Andreev bound state spectra with potential topological phases.

Contribution

It introduces a quantum point contact approach to independently control conductance modes in multi-terminal Josephson junctions, facilitating experimental access to topologically tunable Andreev bound states.

Findings

Achieved independent control of conductance modes between terminals.

Accessed single-mode conductance regime with superconducting coupling.

Established a platform for realizing tunable Andreev bound state spectra.

Abstract

The Andreev bound state spectra of multi-terminal Josephson junctions form an artificial band structure, which is predicted to host tunable topological phases under certain conditions. However, the number of conductance modes between the terminals of multi-terminal Josephson junction must be few in order for this spectrum to be experimentally accessible. In this work we employ a quantum point contact geometry in three-terminal Josephson devices. We demonstrate independent control of conductance modes between each pair of terminals and access to the single-mode regime coexistent with the presence of superconducting coupling. These results establish a full platform on which to realize tunable Andreev bound state spectra in multi-terminal Josephson junctions.