Pseudo Jahn-Teller Origin of Perovskite Multiferroics, Magnetic-Ferroelectric Crossover, and Magnetoelectric Effects: Thed0−d10Problem

Abstract

The conditions of multiferroicity in $d^n$ perovskites are derived from the pseudo Jahn-Teller effect, due to which ferroelectric displacements are triggered by vibronic coupling between ground and excited electronic states of opposite parity but same spin multiplicity; it takes place for some specific $d^n$ configurations and spin states only. In combination with the high-spin–low-spin crossover effect this leads to a novel phenomenon, the magnetic-ferroelectric (multiferroics) crossover which predicts magnetoelectric effects with exciting functionalities including electric magnetization and demagnetization. DOI: http://dx.doi.org/10.1103/PhysRevLett.108.137202 © 2012 American Physical Society