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Titolo:
FIRST PRINCIPLES TOTAL-ENERGY STUDY OF FERROELECTRIC TRANSITIONS IN LINBO3
Autore:
YU JJ; PARK KT;
Indirizzi:
SOGANG UNIV,DEPT PHYS SEOUL 121742 SOUTH KOREA KOOKMIN UNIV,DEPT PHYS SEOUL 136702 SOUTH KOREA
Titolo Testata:
Physica. B, Condensed matter
, volume: 237, anno: 1997,
pagine: 341 - 344
SICI:
0921-4526(1997)237:<341:FPTSOF>2.0.ZU;2-X
Fonte:
ISI
Lingua:
ENG
Soggetto:
QUASIELASTIC LIGHT-SCATTERING; DIELECTRIC-PROPERTIES; PHASE-TRANSITION; LITAO3; TC;
Keywords:
TOTAL ENERGY CALCULATION; FERROELECTRICITY; LINBO3;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
17
Recensione:
Indirizzi per estratti:
Citazione:
J.J. Yu e K.T. Park, "FIRST PRINCIPLES TOTAL-ENERGY STUDY OF FERROELECTRIC TRANSITIONS IN LINBO3", Physica. B, Condensed matter, 237, 1997, pp. 341-344

Abstract

Inspite of its uniaxially symmetric simple crystal structure, there are still dubious arguments on the types and origin of ferroelectric instability in LiNbO3. As a step toward first-principles theoretical studies of ferroelectric transitions, we carried out total energy calculations of LiNbO3 by using the full-potential linearized augmented-plane-wave (FLAPW) method based on the density functional theory within local density approximation. By performing many total energy calculationsof LiNbO3 with various possible configurations of Li and O displacements, we obtained total energy surfaces showing that the independent displacements of Li and O atoms lead to a shallow potential well, while the distortions of the coupled mode u(Li+O) leads to a deep double-well potential, the depth of which is significantly larger than the observed phase-transition temperature T-c. The Li-dipole induced oxygen polarization is suggested to be the origin of such large energy gain by the Li-O coupled distortions. Therefore, it is concluded that the Li displacements coupled to oxygen polarizations may play a crucial role inthe ferroelectric phase transition of LiNbO3.

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Documento generato il 25/06/18 alle ore 17:29:32