Quantum-Material Josephson Junctions: Unconventional Barriers, Emerging Functionality

TL;DR

This paper reviews recent advances in quantum-material Josephson junctions, highlighting how unconventional barriers like magnetic, correlated, and ferroelectric materials enable new functionalities and probe complex many-body physics.

Contribution

It provides a comprehensive overview of how different quantum material barriers enhance Josephson junction capabilities and reveal novel physical phenomena.

Findings

Magnetic barriers enable 0-π-φ states and nonreciprocal transport.

Correlated barriers exhibit field-free Josephson diode behavior.

Ferroelectric barriers allow superconducting memory and memristive effects.

Abstract

Josephson junctions translate quantum phase coherence into an electrical response and underpin superconducting sensors and quantum circuits. In conventional junctions, the barrier acts primarily as a passive weak link, however, when the barrier is a quantum material with its own internal degrees of freedom like magnetism, strong correlations, or switchable polarization, the Josephson effect becomes a sensitive probe of symmetry and many-body physics in the interlayer. Here we review progress in quantum-material Josephson junctions, (QMJJ) focusing on three rapidly advancing barrier families: 1. magnetic barriers, where exchange, noncollinearity, and spin-active scattering enable 0-{\pi}-{\phi} ground states, singlet-triplet conversion, and nonreciprocal transport, 2. correlated barriers, where proximity effects acquire many-body character and recent van der Waals Kagome Mott interlayers exhibit field-free Josephson diode behavior, and 3. ferroelectric and multiferroic barriers, where nonvolatile polarization provides an internal control knob and can produce superconducting memory and memristive dynamics.