Improper origin of polar displacements at CaTiO3 and CaMnO3 Twin Walls

Abstract

Recent interests towards novel functionalities arising at domain walls of ferroic materials naturally call for a microscopic understanding. To this end, first-principles calculations have been performed in order to provide solid evidence of ferroelectricity in the twin walls of nonpolar CaTiO3 and magnetic CaMnO3. We show that ferroelectricity arises from rotation/tilting octahedral distortions --- cooperatively acting at the twin wall in both considered systems --- rather than from a proper secondary ferroelectric instability, as often believed. Our results are in excellent agreement with experimental observations of domain walls in CaTiO3. In addition, we show that magnetic properties at the twin wall in CaMnO3 are also modified, thus suggesting an unexplored route to achieve and detect multiferroic ordering in a single-phase material.

References in corpus (4)

• Restoring the density-gradient expansion for exchange in solids and surfaces
• Generalized gradient approximation for solids and their surfaces
• Engineering multiferroism in CaMnO${}_3$
• Non-$d^0$ Mn-driven ferroelectricity in antiferromagnetic BaMnO${}_3$

Cited by in corpus (6)

• Macroscopic Polarization from Antiferrodistortive Cycloids in Ferroelastic SrTiO${}_3$
• Mechanisms and origin of multiferroicity
• Exchange interactions of CaMnO3 in the bulk and at the surface
• Spin-Phonon Coupling and High Pressure Phase Transitions of RMnO3 (R= Ca and Pr): An Inelastic Neutron Scattering and First Principle Studies
• Electric polarization of magnetic domain walls in magnetoelectrics
• Finite-temperature properties and the hidden ferroelectric $R3c$ phase of bulk CaTiO${}_3$ from second principles