Chiral Pseudo Spin Liquids in Moire Heterostructures

TL;DR

This paper introduces a new platform using moire heterostructures under magnetic fields to realize and control chiral pseudo spin liquids with topological order, enabling experimental exploration of complex quantum phases.

Contribution

It proposes a method to realize and study topologically ordered chiral pseudo spin liquids in moire heterostructures with tunable magnetic flux and strong interactions.

Findings

Identification of layer degree of freedom as pseudo spin maintaining SU(2) symmetry.

Discovery of stable chiral pseudo spin liquid phases induced by magnetic fields.

Demonstration of the system's potential for experimental realization of topological phases.

Abstract

We propose multi-layer moire structures in strong external magnetic fields as a novel platform for realizing highly-tunable, frustrated Hubbard physics with topological order. Identifying the layer degree of freedom as a pseudo spin, allows us to retain SU(2) symmetry while controlling ring-exchange processes and concurrently quenching the kinetic energy by large external magnetic fields. This way, a broad class of interacting Hubbard-Hofstadter states and their transitions can be studied. Remarkably, in the limit of strong interactions the system becomes Mott insulating and we find chiral pseudo spin liquid phases which are induced by the magnetic field. We find that this topologically ordered state remains exceptionally stable towards relevant perturbations. We discuss how layer pseudo-spin can be probed in near-term experiments. As the magnetic flux can be easily tuned in moire systems, our approach provides a promising route towards the experimental realization and control of topologically ordered phases of matter.