Topological Quantum Phase Transitions of Anisotropic Antiferromagnetic Kitaev Model Driven by Magnetic Field

Abstract

The evolution of quantum spin liquid states (QSL) of the anisotropic antiferromagnetic (AFM) Kitaev model with the [001] magnetic field by utilizing the finite-temperature Lanczos method (FTLM) is investigated. In this anisotropic Kitaev model with K X = K Y and K X + K Y + K Z = −3 K (K is the energy unit), due to the competition between anisotropy and magnetic field, the system emerges four exotic quantum phase transitions (QPTs) when K Z = −1.8 and −1.4 K, while only two QPTs when K Z = −0.6 K. At these magnetic-field tuning quantum phase transition points, the low-energy excitation spectrums appear level crossover, and the specific heat, magnetic susceptibility and Wilson ratio display anomalies; accordingly, the topological Chern number may also change. These results demonstrate that the anisotropic interacting Kitaev model with modulating magnetic field displays more rich phase diagrams, in comparison with the isotropic Kitaev model.