铁电体系统中宏观电场结构响应的理论
摘要
我们 developed and implemented a 计算周期绝缘系统受均匀静电场结构响应的形式化方法，基于密度泛函扰动理论(DFPT)。我们考虑 thermodynamic potentials E(R,eta,e) 和 F(R,eta,e)，其对内部结构参数 R 和单元胞应变 eta 的最小化分别可获得在固定电场 e 和极化 P 时的平衡结构。对 E(R,eta,e) 关于 e 的一阶展开导致一种有用的近似，即可通过在固定自发极化 P 的约束下，对结构坐标进行最小化来获得 R(P) 和 eta(P)。为便于此最小化，我们 formulate a modified DFPT scheme such that the computed derivatives of the polarization are consistent with the discretized form of the Berry-phase expression. 我们 then describe the application of this approach to several problems associated with bulk and short-period superlattice structures of ferroelectric materials such as BaTiO3 and PbTiO3. These include the effects of compositionally broken inversion symmetry, the equilibrium structure for high values of polarization, field-induced structural phase transitions, and the lattice contributions to the linear and the non-linear dielectric constants. 这些包括组成破坏反演对称性的效应、高极化值下的平衡结构、场诱导的结构相变，以及晶格对线性和非线性介电常数的贡献。
引用
@article{arxiv.cond-mat/0205442,
title = {Theory of structural response to macroscopic electric fields in ferroelectric systems},
author = {Na Sai and Karin M. Rabe and David Vanderbilt},
journal= {arXiv preprint arXiv:cond-mat/0205442},
year = {2009}
}
备注
19 pages, with 15 postscript figures embedded. Uses REVTEX4 and epsf macros. Also available at http://www.physics.rutgers.edu/~dhv/preprints/sai_pol/index.html