# Gate-Tunable Orbital Magnetism and Competing Superconductivity in Twisted Trilayer Graphene Josephson Junctions

## TL;DR

Researchers study how magnetism and superconductivity compete in twisted graphene devices, revealing new insights into their coexistence.

## Contribution

A new platform using twisted trilayer graphene Josephson junctions is introduced to explore competing superconductivity and orbital magnetism.

## Key findings

- Orbital magnetism in twisted trilayer graphene is confirmed via Hall resistance jumps and current-induced bistability.
- Superconductivity dominates over orbital magnetism at higher carrier densities and displacement fields.
- Nonreciprocal Josephson transport provides evidence of orbital magnetic states in weak links.

## Abstract

Twisted trilayer graphene (TTG) provides a tunable moiré
platform to study correlated phases emerging from flat-band physics.
Here, we investigate the interplay between superconductivity and spontaneous
orbital magnetism (OM) in alternating TTG devices with intermediate
twist angles (1.38–1.44°). Using electrostatically defined
Josephson junctions, we demonstrate that OM, stabilized near the charge
neutrality point (CNP), competes with gate-induced superconductivity.
The OM phase is characterized by sharp jumps in Hall resistance, current-induced
bistability, and a Curie–Bloch temperature dependence, indicating
broken time-reversal symmetry. Additionally, nonreciprocal Josephson
transportmanifested as asymmetric Fraunhofer patterns and
a superconducting diode effectprovides independent evidence
of an orbital magnetic state confined to the weak link. The observed
critical temperature hierarchy, where superconductivity dominates
over OM at higher carrier densities and displacement fields, reveals
a tunable competition between two broken-symmetry ground states. Our
findings establish alternating TTG Josephson devices as a minimal
and versatile platform to probe the coexistence of magnetism and superconductivity
in engineered moiré systems.