Low-temperature anharmonicity of barium titanate: A path-integral molecular-dynamics study

被引：13

作者：

Geneste, Gregory ^{[1
]}

Dammak, Hichem ^{[2
,3
]}

Hayoun, Marc ^{[3
]}

Thiercelin, Mickael ^{[2
]}

机构：

[1] CEA, DAM, DIF, F-91297 Arpajon, France

[2] Ecole Cent Paris, Lab Struct Proprietes & Modelisat Solides, Ctr Natl Rech Sci, Unite Mixte Rech 8580, F-92295 Chatenay Malabry, France

[3] Ecole Polytech, Solides Irradies Lab, Ctr Natl Rech Sci, Commissariat Energie Atom, F-91128 Palaiseau, France

来源：

PHYSICAL REVIEW B | 2013年 / 87卷 / 01期

关键词：

CONSTANT-PRESSURE; PIEZOELECTRIC PROPERTIES; QUANTUM PARAELECTRICITY; LANGEVIN DYNAMICS; PHASE-TRANSITIONS; SINGLE-CRYSTALS; BATIO3; SRTIO3; ALGORITHMS; PRINCIPLES;

D O I：

10.1103/PhysRevB.87.014113

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

We investigate the influence of quantum effects on the dielectric and piezoelectric properties of barium titanate in its (low-temperature) rhombohedral phase, and show the strongly anharmonic character of this system even at low temperature. For this purpose, we perform path-integral molecular-dynamics simulations under fixed pressure and fixed temperature, using an efficient Langevin thermostat-barostat, and an effective Hamiltonian derived from first-principles calculations. The quantum fluctuations are shown to significantly enhance the static dielectric susceptibility (approximate to by a factor of 2) and the piezoelectric constants, reflecting the strong anharmonicity of this ferroelectric system even at very low temperature. The slow temperature-evolution of the dielectric properties observed below approximate to 100 K is attributed (i) to zero-point energy contributions and (ii) to harmonic behavior if the quantum effects are turned off. DOI: 10.1103/PhysRevB.87.014113

引用

页数：9

共 42 条

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