Tomonaga-Luttinger liquid in quasi-one-dimensional antiferromagnet BaCo2V2O8 in magnetic fields

TL;DR

This paper explores the Tomonaga-Luttinger-liquid behavior in the quasi-one-dimensional antiferromagnet BaCo2V2O8 under magnetic fields, using the Bethe ansatz to connect theoretical predictions with experimental observations.

Contribution

It provides a detailed theoretical analysis of the 1D XXZ Heisenberg-Ising model in magnetic fields, linking Bethe ansatz solutions to experimental data on BaCo2V2O8.

Findings

Observation of a magnetization minimum near the critical field.

T-linear specific heat below the magnetization minimum.

Field-dependent divergence exponent of NMR relaxation rate.

Abstract

Motivated by recent studies on the quasi-one-dimensional (1D) antiferromagnet BaCo2V2O8, we investigate the Tomonaga-Luttinger-liquid properties of the 1D S=1/2 XXZ Heisenberg-Ising model in magnetic fields. By using the Bethe ansatz solution, thermodynamic quantities and the divergence exponent of the NMR relaxation rate are calculated. We observe a magnetization minimum as a function of temperature (T) close to the critical field. As the magnetic field approaches the critical field, the minimum temperature asymptotically approaches the universal relation in agreement with the recent results by Maeda et al. in Phys. Rev. Lett. 99 (2007) 057205. We observe T-linear specific heat below the temperature of the magnetization minimum. The field dependence of its coefficient agrees with the results based on conformal field theory. The field dependence of the divergence exponent of the NMR relaxation rate with decreasing temperature is obtained, indicating a change in the critical properties. The results are discussed in connection with experiments on BaCo2V2O8.