Reference : First-principles study of competing ferroelectric and antiferroelectric instabilities in...

	Document type :	Scientific journals : Article
	Discipline(s) :	Physical, chemical, mathematical & earth Sciences : Physics
	To cite this reference:	http://hdl.handle.net/2268/69227

Title :	First-principles study of competing ferroelectric and antiferroelectric instabilities in BaTiO3/BaO superlattices
Language :	English
Author, co-author :	Bousquet, Eric [Université de Liège - ULg > Département de physique > Physique théorique des matériaux >]
	Junquera, Javier [Universidad de Cantabria, Santander, Spain > Departamento de Ciencias de la Tiera y Fisica de la Materia Condensata > > >]
	Ghosez, Philippe [Université de Liège - ULg > Département de physique > Physique théorique des matériaux >]
Publication date :	2010
Journal title :	Physical Review. B : Condensed Matter
Publisher :	American Institute of Physics
Volume :	82
Issue/season :	4
Pages :	045426
Audience :	International
ISSN :	0163-1829
City :	New York
Country :	NY
Abstract :	[en] We report a first-principles study of (BaTiO3) m/ (BaO) n superlattices for a wide range of periodicities m/n. We show that such a system develops a polar zone-center instability for sufficiently large m/n ratio, which can be understood, at least qualitatively, from a simple electrostatic model and should lead to a ferroelectric ground state. However, the analysis of the phonon-dispersion curves also points out the appearance of stronger antiferroelectric instabilities at the zone boundaries around m=4, before the critical ratio for ferroelectricity is reached and which still dominate beyond it. The dominant character of the antiferroelectric instability is explained from the depolarizing field which hardens the ferroelectric mode. This analysis allows us to predict that, (BaTiO3) m/ (BaO) n superlattices should present an antiferroelectric ground state for m larger than 4, which should smoothly evolve to a multidomain structure for increasing m values and only become ferroelectric for large m.
Research units :	Physique Théorique des Matériaux
Name of the research project :	EU-OxIDes (FP7), PAI-QCN (P6/42)
Permalink :	http://hdl.handle.net/2268/69227

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