Kagome lattice antiferromagnets and Dzyaloshinsky-Moriya interactions

TL;DR

This paper investigates how in-plane and out-of-plane Dzyaloshinsky-Moriya interactions influence the thermodynamic properties of the spin-1/2 kagome Heisenberg antiferromagnet, providing insights into experimental observations in ZnCu3(OH)6Cl2.

Contribution

It offers a detailed analysis of DM interactions' effects on thermodynamics, highlighting their distinct impact compared to other perturbations and constraining their parameters based on experimental data.

Findings

DM interactions cause diverse thermodynamic behaviors.

The susceptibility upturn is explained by D_p>|D_z|.

Specific heat measurements constrain DM parameters.

Abstract

We study the consequences of in-plane (D_p) and out-of-plane (D_z) Dzyaloshinsky-Moriya (DM) interactions on the thermodynamic properties of spin-1/2} Heisenberg model on the kagome lattice using numerical linked cluster expansions and exact diagonalization, and contrast them with those of other perturbations such as exchange anisotropy and dilution. We find that different combinations of the DM anisotropies lead to a wide variety of thermodynamic behavior, which are quite distinct from those of most other perturbations. We argue that the sudden upturn seen experimentally in the susceptibility of the material ZnCu3(OH)6Cl2 can be understood in terms of Dzyaloshinsky-Moriya anisotropies with D_p>|D_z|. We also show that the measured specific heat of the material puts further constraints on the allowed DM parameters.