Topological quantum phase transitions of anisotropic AFM Kitaev model driven by magnetic field

TL;DR

This paper studies how magnetic fields induce topological quantum phase transitions in an anisotropic antiferromagnetic Kitaev model, revealing multiple gapless quantum spin liquid phases and their dependence on magnetic field strength.

Contribution

It provides the first detailed analysis of magnetic field-driven topological phase transitions in anisotropic AFM Kitaev models using finite-temperature Lanczos method.

Findings

Multiple quantum spin liquid phases identified under varying magnetic fields.

Critical magnetic fields increase monotonically with Kitaev coupling.

Magnetic field can modulate anisotropic Kitaev materials effectively.

Abstract

We investigate the quantum spin liquid (QSL) ground state of anisotropic Kitaev model with antiferromagnetic (AFM) coupling under the $[001]$ magnetic field with the finite-temperature Lanczos method (FTLM). In this anisotropic AFM Kitaev model with $K_{X}=K_{Y}$, $K_{X}+K_{Y}+K_{Z}=-3K$, and $K_{Z}<-K$, with magnetic field increasing, the gapped QSL experiences a transition to a gapless QSL at $h_{c1}=g\mu_{B}H_{z1}/K$, to another gapless QSL with $C_{6}$ rotational symmetry at $h_{c2}$, and to a new $U(1)$ gapless QSL between $h_{c3}$ and $h_{c4}$, respectively. These indicate that magnetic field could first turn the anisotropic gapped or gapless QSL back into the isotropic $C_{6}$ gapless one and then make it to undergo the similar evolution as the isotropic case. Moreover, the critical magnetic fields $h_{c1}$, $h_{c2}$, $h_{c3}$, and $h_{c4}$ come up monotonically with the increasing Kitaev coupling; this suggests that the magnetic field can be applied to the modulation of the anisotropic Kitaev materials.