Magnonic analog of the Edelstein effect in antiferromagnetic insulators
Bo Li, Alexander Mook, Aldo Raeliarijaona, Alexey A. Kovalev
Abstract
We investigate the nonequilibrium spin polarization due to a temperature gradient in antiferromagnetic insulators, which is the magnonic analog of the inverse spin-galvanic effect of electrons. We derive a linear-response theory of a temperature-gradient-induced spin polarization for collinear and noncollinear antiferromagnets, which comprises both extrinsic and intrinsic contributions. We apply our theory to several noncentrosymmetric antiferromagnetic insulators, i.e., to a one-dimensional antiferromagnetic spin chain, a single layer of kagome noncollinear antiferromagnet, e.g., ${\text{KFe}}_{3}{(\text{OH})}_{6}{({\text{SO}}_{4})}_{2}$, and a noncollinear breathing pyrochlore antiferromagnet, e.g., ${\mathrm{LiGaCr}}_{4}{\mathrm{O}}_{8}$. The shapes of our numerically evaluated response tensors agree with those implied by the magnetic symmetry. Assuming a realistic temperature gradient of $10\phantom{\rule{0.28em}{0ex}}\text{K/mm}$, we find two-dimensional spin densities of up to $\ensuremath{\sim}{10}^{6}\ensuremath{\hbar}/{\text{cm}}^{2}$ and three-dimensional bulk spin densities of up to $\ensuremath{\sim}{10}^{14}\ensuremath{\hbar}/{\text{cm}}^{3}$, encouraging an experimental detection.