Magnetic field induced quantum phases in a tensor network study of Kitaev magnets

TL;DR

This study uses tensor network methods to explore magnetic field-induced quantum phases in Kitaev magnets, revealing a band of emergent states that align with experimental observations of half-quantized thermal Hall conductivity.

Contribution

The paper introduces a tensor network approach to identify and characterize multiple quantum phases in Kitaev models under magnetic fields, expanding understanding beyond known phases.

Findings

Identification of various quantum ground states in magnetic fields

Discovery of a band of emergent quantum phases

Correlation with experimental thermal Hall effects

Abstract

Recent discovery of the half quantized thermal Hall conductivity in $\alpha$-RuCl$_3$, a candidate material for the Kitaev spin liquid, suggests the presence of a highly entangled quantum state in external magnetic fields. This field induced phase appears between the low field zig-zag magnetic order and the high field polarized state. Motivated by this experiment, we study possible field induced quantum phases in theoretical models of the Kitaev magnets, using the two dimensional tensor network approach or infinite tensor product states. We find various quantum ground states in addition to the chiral Kitaev spin liquid occupying a small area in the phase diagram. They form a band of emergent quantum phases in an intermediate window of external magnetic fields, somewhat reminiscent of the experiment. We discuss the implications of these results in view of the experiment and previous theoretical studies.