Magnetic order and spin excitations in the Kitaev--Heisenberg model on the honeycomb lattice

TL;DR

This paper analyzes the magnetic order and spin excitations in the Kitaev-Heisenberg model on a honeycomb lattice, providing theoretical insights into phase transitions and comparing results with experimental data on Na2IrO3.

Contribution

It offers a detailed RPA-based calculation of spin-wave spectra, magnetization, and transition temperatures for various phases in the model, connecting theory with experiments.

Findings

Calculated spin-wave excitation spectra for different phases.

Compared Néel temperature and magnetization with experimental data.

Identified phase-dependent magnetic properties in the model.

Abstract

We consider the quasi-two-dimensional pseudo-spin-1/2 Kitaev - Heisenberg model proposed for A2IrO3 (A=Li, Na) compounds. The spin-wave excitation spectrum, the sublattice magnetization, and the transition temperatures are calculated in the random phase approximation (RPA) for four different ordered phases, observed in the parameter space of the model: antiferomagnetic, stripe, ferromagnetic, and zigzag phases. The N\'{e}el temperature and temperature dependence of the sublattice magnetization are compared with the experimental data on Na2IrO3.