Effects of the Dzyaloshinskii-Moriya interaction on low energy magnetic excitations in copper benzoate

TL;DR

This study investigates how the Dzyaloshinskii-Moriya interaction influences low-energy magnetic excitations in copper benzoate, providing a detailed quantitative analysis and predictions for experimental validation.

Contribution

It offers a comprehensive quantitative account of the field dependence of spin gaps in copper benzoate due to DM interaction, without assuming additional interactions.

Findings

Spin gap varies as H^{2/3} with a specific logarithmic correction.

Staggered magnetization varies as H^{1/3}.

A predicted crossover to strong field behavior for future experiments.

Abstract

We have investigated the physical effects of the Dzyaloshinskii-Moriya (DM) interaction in copper benzoate. In the low field limit, the spin gap is found to vary as $H^{2/3}\ln ^{1/6}(J/\mu_BH_s)$ ($H_s$: an effective staggered field induced by the external field $H$)in agreement with the prediction of conformal field theory, while the staggered magnetization varies as $H^{1/3}$ and the $\ln^{1/3}(J/\mu_BH_s)$ correction predicted by conformal field theory is not confirmed.The linear scaling relation between the momentum shift and the magnetization is broken. We have determined the coupling constant of the DM interaction and have given a complete quantitative account for the field dependence of the spin gaps along all three principal axes, without resorting to additional interactions like interchain coupling. A crossover to strong applied field behavior is predicted for further experimental verification.