Tunable moire spinons in magnetically encapsulated twisted van der Waals quantum spin-liquids

TL;DR

This paper proposes a twisted van der Waals heterostructure with quantum spin-liquid bilayers encapsulated between ferromagnetic insulators, demonstrating controllable spinon flat bands and topological states driven by twist and exchange effects.

Contribution

It introduces a novel twisted heterostructure platform for exploring and controlling moire spinon phenomena in quantum spin liquids.

Findings

Emergence of spinon flat bands and topological states in the heterostructure.

Control of spinon bandstructure via exchange proximity effect.

Potential for characterizing quantum spin-liquid states using tunneling spectroscopy.

Abstract

Quantum spin-liquid van der Waals magnets such as TaS$_2$, TaSe$_2$, and RuCl$_3$ provide a natural platform to explore new exotic phenomena associated with spinon physics, whose properties can be controlled by exchange proximity with ferromagnetic insulators such as CrBr$_3$. Here we put forward a twisted van der Waals heterostructure based on a quantum spin-liquid bilayer encapsulated between ferromagnetic insulators. We demonstrate the emergence of spinon flat bands and topological spinon states in such heterostructure, where the emergence of a topological gap is driven by the twist. We further show that the spinon bandstructure can be controlled via exchange proximity effect to the ferromagnetic leads. We finally show how by combining small magnetic fields with tunneling spectroscopy, magnetically encapsulated heterostructures provide a way of characterizing the nature of the quantum spin-liquid state. Our results put forward twisted quantum spin-liquid bilayers as potential platforms for exotic moire spinon phenomena, demonstrating the versatility of magnetic van der Waals heterostructures.