Ta2O5 polymorphs: Structural motifs and dielectric constant from first principles

被引：39

作者：

Andreoni, Wanda ^{[1
]}

Pignedoli, Carlo A. ^{[1
,2
]}

机构：

[1] IBM Res Zurich, CH-8803 Ruschlikon, Switzerland

[2] Empa, Swiss Fed Labs Mat Testing & Res, CH-8600 Dubendorf, Switzerland

来源：

APPLIED PHYSICS LETTERS | 2010年 / 96卷 / 06期

关键词：

ab initio calculations; crystal growth; density functional theory; permittivity; polymorphism; Raman spectra; tantalum compounds; GENERALIZED GRADIENT APPROXIMATION; THIN-FILMS;

D O I：

10.1063/1.3308475

中图分类号：

O59 [应用物理学];

学科分类号：

摘要：

Using large-scale simulations based on density-functional theory we determine the structural properties of several polymorphs of tantalia, their vibrational spectra and dielectric properties. Our calculations indicate that structurally distinct configurations can coexist, having coordination polyhedra that are dissimilar or have different relative arrangements. Interpolyhedra vibrations are discovered to be responsible for sizable changes of the static dielectric constant from one polymorph to the other. Our results for the dielectric constant (both at high and low frequency) are in excellent agreement with experiment and provide an explanation for the different measured values and their claimed dependence on growth conditions.

引用

页数：3

共 35 条

[1] Rietveld analysis of X-ray diffraction pattern from β-Ta2O5 oxide [J].