Reconfigurable chiral superconductivity

TL;DR

This study demonstrates reconfigurable chiral superconductivity in rhombohedral multilayer graphene through nanoscale magnetic imaging, revealing domain structures, TRS breaking, and controllable chirality states.

Contribution

It provides direct magnetic evidence of TRS breaking and shows how isospin-polarized domains influence chiral superconductivity in rhombohedral graphene.

Findings

Detection of isospin-polarized domains using nanoscale SQUID magnetometry.

Correlation between domain wall proliferation and the onset of CSC.

Reversible control of chiral domain states via ultra low current switching.

Abstract

Rhombohedral multilayer graphene at high displacement fields hosts superconductivity emerging from a spin valley polarized quarter metal, with transport signatures suggestive of time reversal symmetry (TRS) breaking and chiral superconductivity (CSC). These observations have motivated proposals of topological superconductivity and non-Abelian quasiparticles, yet direct magnetic evidence and microscopic insight into the superconducting state remain lacking, limiting understanding of this unique state. Here we use nanoscale SQUID on tip magnetometry to image isospin-polarized domains in rhombohedral pentalayer graphene and establish CSC via spatially resolved thermodynamic detection of TRS breaking. We find that the density at which domain walls proliferate at elevated temperatures coincides with the onset of CSC, indicating an underlying transition in the parent state that both induces superconductivity and reduces domain wall energy. We further show that the chiral domain structure in the superconducting phase is inherited from the isospin-polarized parent state. Strikingly, the CSC phase exhibits multiple transport regimes governed by configurations of chiral domains separated by highly resistive domain walls. We demonstrate deterministic, ultra low current control of these domains, enabling reversible switching between states of opposite chirality a defining CSC property absent in other superconductors. These results establish rhombohedral graphene as a unique platform for reconfigurable CSC and ultra low power electronic functionality based on controllable isospin textures.