Susceptibility anisotropy and its disorder evolution in models for Kitaev materials

Abstract

Mott insulators with strong spin-orbit coupling display a strongly anisotropic response to applied magnetic fields. This applies in particular to Kitaev materials, with $\alpha$-RuCl${}_3$ and Na${}_2$IrO${}_3$ representing two important examples. Both show a magnetically ordered zigzag state at low temperatures, and considerable effort has been devoted to properly modeling these systems in order to identify routes towards realizing a quantum spin liquid. Here, we investigate the relevant Heisenberg-Kitaev-$\Gamma$ model primarily at elevated temperatures, focusing on the characteristic anisotropy between the in-plane and out-of-plane uniform susceptibility. For $\alpha$-RuCl${}_3$, we find that the experimentally observed anisotropy, including its temperature dependence, can be reproduced by combining a large off-diagonal ${\Gamma }_1$ coupling with a moderate $g$-factor anisotropy. Moreover, we study in detail the effect of magnetic dilution and provide predictions for the doping evolution of the temperature-dependent susceptibilities.

13 pages, 6 figures. Published version

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Cited by in corpus (3)

• Symmetry Analysis of Tensors in the Honeycomb Lattice of Edge-Sharing Octahedra
• Interplay of magnetic field and trigonal distortion in the honeycomb $\Gamma$ model: Occurrence of a spin-flop phase
• Nesting instability of gapless U(1) spin liquids with spinon Fermi pockets in two dimensions