Magnetoelectric response of multiferroic BiFeO3 and related materials from first-principles calculations.

We present a first-principles scheme for computing the magnetoelectric response of multiferroics. We apply our method to BiFeO3 (BFO) and related compounds in which Fe is substituted by other magnetic species. We show that under certain relevant conditions--i.e., in the absence of incommensurate spin modulation, as in BFO thin films and some BFO-based solid solutions--these materials display a large linear magnetoelectric response. Our calculations reveal the atomistic origin of the coupling and allow us to identify the most promising strategies to enhance it.