A range of honeycomb-lattice compounds has been proposed and investigated in the search for a topological Kitaev spin liquid. However, sizable Heisenberg interactions and additional symmetry-allowed exchange anisotropies in the magnetic Hamiltonian of these potential Kitaev materials push them away from the pure Kitaev spin-liquid state. Particularly the Kitaev-to-Heisenberg coupling ratio is essential in this respect. With the help of advanced quantum-chemistry methods, we explore how the magnetic coupling ratios depend on pressure in several honeycomb compounds (Na2IrO3, β-Li2IrO3, and α-RuCl3). We find that the Heisenberg and Kitaev terms are affected differently by uniform pressure or strain: the Kitaev component increases more rapidly than the Heisenberg counterpart. This provides a scenario where applying pressure or strain can stabilize a spin liquid in such materials.
@article{arxiv.1802.01051,
title = {Pressure-tuned magnetic interactions in honeycomb Kitaev materials},
author = {Ravi Yadav and Stephan Rachel and Liviu Hozoi and Jeroen van den Brink and George Jackeli},
journal= {arXiv preprint arXiv:1802.01051},
year = {2018}
}