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arXiv · 1911.03408

Giant anisotropy of Gilbert damping in a Rashba honeycomb antiferromagnet

M. Baglai·R. J. Sokolewicz·A. Pervishko·M. I. Katsnelson·O. Eriksson·D. Yudin·M. Titov
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Abstract

Giant Gilbert damping anisotropy is identified as a signature of strong Rashba spin-orbit coupling in a two-dimensional antiferromagnet on a honeycomb lattice. The phenomenon originates in spin-orbit induced splitting of conduction electron subbands that strongly suppresses certain spin-flip processes. As a result, the spin-orbit interaction is shown to support an undamped non-equilibrium dynamical mode that corresponds to an ultrafast in-plane N\'eel vector precession and a constant perpendicular-to-the-plane magnetization. The phenomenon is illustrated on the basis of a two dimensional $s$-$d$ like model. Spin-orbit torques and conductivity are also computed microscopically for this model. Unlike Gilbert damping these quantities are shown to reveal only a weak anisotropy that is limited to the semiconductor regime corresponding to the Fermi energy staying in a close vicinity of antiferromagnetic gap.

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M. Baglai, R. J. Sokolewicz, A. Pervishko, M. I. Katsnelson, O. Eriksson, D. Yudin, M. Titov. 2019-11-08. Giant anisotropy of Gilbert damping in a Rashba honeycomb antiferromagnet. https://doi.org/10.1103/physrevb.101.104403

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