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arXiv 0709.3104cond-mat.mtrl-scicond-mat.dis-nn
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混合半导体晶格动力学的线性化力常数方法

Linearized force constants method for lattice dynamics in mixed semiconductors

Ayoub Nassour, Joseph Hugel, A. V. Postnikov

摘要:

本文根据第一性原理初步弛豫的原子结构,提出了一种计算混合半导体合金声子谱的简单而精确的方法,并对(Zn,Be)Se和(Ga,In)As固溶体进行了检验。该方法使用的观察,原子间的力常数,从头计算的一些微观配置中引用的系统,显示出明确的线性变化的主要(对角线)值的原子间的力常数与相应的键长。我们制定了简单的规则,如何恢复的力常数矩阵在其本地(键相关)坐标系的各个3 × 3的子块,以及如何将它们转换到一个全球(晶胞相关)坐标系。测试计算64个原子的超晶胞代表不同浓度的(Zn,Be)Se和(Ga,In)As表明,声子频率和组成的本征矢量是忠实地再现在一个线性化的力常数计算,相比真正的从头计算。

英文摘要:

A simple and accurate method of calculating phonon spectra in mixed semiconductors alloys, on the basis of preliminarily (from first principles) relaxed atomic structure, is proposed and tested for (Zn,Be)Se and (Ga,In)As solid solutions. The method uses an observation that the interatomic force constants, calculated ab initio for a number of microscopic configurations in the systems cited, show a clear linear variation of the main (diagonal) values of the interatomic force constants with the corresponding bond length. We formulate simple rules about how to recover the individual 3x3 subblocks of the force constants matrix in their local (bonds-related) coordinate systems and how to transform them into a global (crystal cell-related) coordinate system. Test calculations done for 64-atom supercells representing different concentrations of (Zn,Be)Se and (Ga,In)As show that the phonon frequencies and compositions of eigenvectors are faithfully reproduced in a linearized force constants calculation, as compared to true ab initio calculations.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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