Electric-field control of magnetic anisotropies: application to Kitaev spin liquids*

Magnetic anisotropies are a direct descendent of the spin-orbit coupling. Recently, magnetic anisotropies have enjoyed renewed theoretical and experimental interests for their essential roles in topological states of magnetic materials such as Kitaev spin liquids. Kitaev spin liquids show interesting phenomena under external fields. For example, DC magnetic fields can generate the Majorana mass gap in the Kitaev spin liquid. The Kitaev material under magnetic fields thus behaves as a Majorana Chern insulator accompanied by quantized thermal edge currents. The Chern number depends on non-Kitaev interactions such as off-diagonal symmetric magnetic anisotropies. This presentation discusses a microscopic quantum theory of DC electric-field controls of magnetic anisotropies in Kitaev materials. Our theoretical framework is generic and applicable to a broad class of magnetic Mott insulators. When applied to Kitaev materials, our microscopic theory predicts that the DC electric field controls the off-diagonal symmetric magnetic anisotropy and an antisymmetric one (the Dzyaloshinskii-Moriya interaction).