<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>α</mml:mi><mml:mo>−</mml:mo><mml:msub><mml:mrow><mml:mi mathvariant="normal">RuCl</mml:mi></mml:mrow><mml:mn>3</mml:mn></mml:msub></mml:math>: A spin-orbit assisted Mott insulator on a honeycomb lattice

Abstract

We examine the role of spin-orbit coupling in the electronic structure of $\ensuremath{\alpha}\ensuremath{-}{\mathrm{RuCl}}_{3}$, in which Ru ions in $4{d}^{5}$ configuration form a honeycomb lattice. Our x-ray absorption spectroscopy measurements at the Ru $L$ edges exhibit distinct spectral features associated with the presence of substantial spin-orbit coupling, as well as an anomalously large branching ratio. Furthermore the measured optical spectra can be described very well with first-principles electronic structure calculations obtained by taking into account both spin-orbit coupling and electron correlations. We propose that $\ensuremath{\alpha}\ensuremath{-}{\mathrm{RuCl}}_{3}$ is a spin-orbit assisted Mott insulator, and that the bond-dependent Kitaev interaction may be important for understanding magnetism of this compound.

The authors' abstract, as published at the source. Physical Review B, 2014 · DOI ↗