Disordered crystals from first principles I: Quantifying the configuration space
Disordered crystals from first principles I: Quantifying the configuration space
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DOI：
10.1016/j.aop.2018.01.016
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发表时间：
2018-04-01
影响因子：
3
通讯作者：
Prodan, Emil
中科院分区：
文献类型：
--
作者：
Kuehne, Thomas D.;Prodan, Emil
这项工作是关于有限温度下电子在晶体中输运的第一性原理计算基础的项目的第一章。我们感兴趣的是大多数电子元件运行的温度范围，即室温及以上。其目的是将从头算分子动力学和均匀热力学相的有限温度久保公式相结合的预测性第一原理公式。这个公式的输入是定义热力学晶相的遍历动力系统(Omega，G，Dp)，其中Omega是原子自由度的组态空间，G是作用在Omega上的空间群，Dp是相对于G作用量的遍历Gibbs度量。本工作发展了一种从第一性原理量化(Omega，G，DP)的算法方法。以硅晶体为例，我们发现Gibbs度量具有非常好的多变量正态分布特征，可以使用少量的参数来量化。后者是在不同温度下计算的，并以表格的形式传达。使用这张表，人们可以产生巨大而准确的热无序原子组态，例如，作为随后的电子自由度模拟的输入。(C)2018 Elsevier Inc.保留所有权利。
This work represents the first chapter of a project on the foundations of first-principle calculations of the electron transport in crystals at finite temperatures. We are interested in the range of temperatures, where most electronic components operate, that is, room temperature and above. The aim is a predictive first principle formalism that combines ab-initio molecular dynamics and a finite-temperature Kubo-formula for homogeneous thermodynamic phases. The input for this formula is the ergodic dynamical system (Omega, G, dP) defining the thermodynamic crystalline phase, where Omega is the configuration space for the atomic degrees of freedom, G is the space group acting on Omega and dP is the ergodic Gibbs measure relative to the G-action. The present work develops an algorithmic method for quantifying (Omega, G, dP) from first principles. Using the silicon crystal as a working example, we find the Gibbs measure to be extremely well characterized by a multivariate normal distribution, which can be quantified using a small number of parameters. The latter are computed at various temperatures and communicated in the form of a table. Using this table, one can generate large and accurate thermally-disordered atomic configurations to serve, for example, as input for subsequent simulations of the electronic degrees of freedom. (C) 2018 Elsevier Inc. All rights reserved.