Ab Initio Cycloidal and Chiral Magnetoelectric Responses in Cr$_{2}$O$_{3}$

摘要

We present a thorough density functional theory study of the magneto-electric(ME) effect in Cr$_{2}$O$_{3}$. The spin-lattice ME tensor $\alpha$ wasdetermined in the low-field and spin flop (SF) phases, using the method ofdynamical magnetic charges, and found to be the sum of three distinctcomponents. Two of them, a large relativistic "cycloidal" term and a smalllongitudinal term, are independent on the spin orientation. The third, onlyactive in the SF phases is also of relativistic origin and arises frommagnetic-field-induced chirality, leading to a non-toroidal ME response.