Reference : Electrical properties of improper ferroelectrics from first principles
Scientific journals : Article
Physical, chemical, mathematical & earth Sciences : Physics
Electrical properties of improper ferroelectrics from first principles
Stengel, Massimiliano []
Fennie, Craig J. []
Ghosez, Philippe mailto [Université de Liège - ULg > Département de physique > Physique théorique des matériaux >]
Physical Review. B, Condensed Matter and Materials Physics
American Physical Society
Yes (verified by ORBi)
[en] We study the interplay of structural and polar distortions in hexagonalYMnO3 and short-period PbTiO3/SrTiO3 (PTO/STO) superlattices by means of first-principles calculations at constrained electric displacement field D. We find that in YMnO3 the tilts of the oxygen polyhedra produce a robustly polar ground state, which persists at any choice of the electrical boundary conditions. Conversely, in PTO/STO the antiferrodistortive instabilities alone do not break inversion symmetry, and open-circuit boundary conditions restore a nonpolar state.We suggest that this qualitative difference naturally provides a route to rationalizing the concept of “improper ferroelectricity” from the point of view of first-principles theory. We discuss the implications of our arguments for the design of novel multiferroic materials with enhanced functionalities and for the symmetry analysis of the phase transitions.
CECI ; Tier-1

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