Texture-induced spin-orbit coupling and Skyrmion-electron bound states in a N\'eel antiferromagnet

Abstract

We derive effective-mass electron Hamiltonian for a N\'eel antiferromagnet in the presence of a smooth texture of the staggered magnetization. For certain locations of electron band extrema, the texture produces a peculiar and anomalously strong spin-orbit coupling of the scale $\hbar v / L$, with $v$ the Fermi velocity and $L$ the characteristic length scale of the texture. For a Skyrmion texture, this coupling generates electron bound states, whose energy scale is given by the gap $\Delta$ in the electron spectrum. With dopant carriers, such bound states turn the Skyrmion into a charged particle, that can be manipulated by electric field.