2000 character limit reached
Hybrid Improper Ferroelectricity: A Mechanism for Controllable Magnetization-Polarization Coupling (1007.1003v2)
Published 6 Jul 2010 in cond-mat.mtrl-sci
Abstract: First-principles calculations are presented for the layered perovskite Ca$_3$Mn$_2$O$_7$. The results reveal a rich set of coupled structural, magnetic and polar domains in which oxygen octahedron rotations induce ferroelectricity, magnetoelectricity and weak-ferromagnetism. The key point is that the rotation distortion is a combination of two non-polar modes with different symmetries. We use the term "hybrid" improper ferroelectricity to describe this phenomenon and discuss how control over magnetism is achieved through these functional antiferrodistortive octahedron rotations.