Software tools for thermodynamic calculation of mechanically unstable phases from first-principles data
Software tools for thermodynamic calculation of mechanically unstable phases from first-principles data
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DOI：
10.1016/j.cpc.2019.01.008
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发表时间：
2020-01-01
影响因子：
6.3
通讯作者：
van de Walle, Axel
中科院分区：
文献类型：
--
作者：
Kadkhodaei, Sara;van de Walle, Axel
本文介绍了P-4软件包，一套软件工具，自动化的过程中的机械不稳定相的振动自由能计算。分段多项式势分配（P-4）方法是近年来发展起来的一种研究固溶体和化合物中声子不稳定性的方法。该方法有效地探讨了系统的从头算能量表面的离散采样的局部极小值，这是通过一个约束的谐波晶格动力学方法与连续采样的这些局部极小值附近相结合。该工具包获得的自由能值可用于热力学评估和相图计算。作为一个独特的优势，它提供了一个工具来计算振动自由能在很宽的组成范围内的合金。这一特点实际上是不能实现的，仅仅依靠蛮力分子动力学或随机抽样techniques.Program summaryProgram Title：P-4（Piecewise Polynomial Potential Partitioning）Program Files doi：http://dx.doi.org/10.17632/sgfyhyrmjb.1Licensing条款：CC by 4.0编程语言：C++ and Bash问题性质：尽管存在声子不稳定性，但许多技术相关的材料在足够高的温度下变得热稳定。这使得标准的晶格动力学方法不足以描述这些材料中的稳定熵效应。解决方法：我们实现了分段多项式势分配方法[1]，该方法有助于热力学计算在有限温度下由于非谐熵效应而稳定的机械不稳定材料。我们的模型的当前版本与密度泛函理论代码VASP接口[2]。其他评论包括限制和不寻常的功能：P-4代码需要内置到ATAT工具包中[3]。文档中给出了如何将P-4安装到ATAT工具包中的说明。程序文件的其他链接：http://go.uic.edu/p4，https：//doLorg/10.26300/zs 0 n-2c 84。参考文献：[1] Sara Kadkhodaei，Qi-Jun Hong，and阿克塞尔van货车de Walle，Free energy calculation of mechanical unstable but dynamic stabilized bcc titanium.物理学修订版B，95（2017）064101[2] G。Kresse和J. Furthmuller，使用平面波基组进行从头算总能量计算的有效迭代方案。物理评论B 54（1996）11169[3] A.货车de Walle和M. Asta和G.合金理论自动化工具包：用户指南。Calphad 26（2002）539-553（C）2019 Elsevier B. V.保留所有权利。
This paper introduces the P-4 software package, a set of software tools that automate the process of vibrational free energy calculation for mechanically unstable phases. The Piecewise Polynomial Potential Partitioning (P-4) method is a recently developed method that tackles the issue of phonon instabilities in solid solutions and compounds. The method efficiently explores the system's ab-initio energy surface by discrete sampling of local minima, which is combined with a continuous sampling of the vicinity of these local minima via a constrained harmonic lattice dynamic approach. The free energy values obtained by this toolkit can be used in thermodynamic assessments and phase diagram calculations. As a unique advantage, it provides the tool to calculate the vibrational free energy in a wide composition range in alloys. This feature is not practically achievable by relying only on brute-force molecular dynamics or random sampling techniques.Program summaryProgram Title: P-4 (Piecewise Polynomial Potential Partitioning)Program Files doi: http://dx.doi.org/10.17632/sgfyhyrmjb.1Licensing provisions: CC by 4.0Programming language: C++ and BashNature of problem: A number of technologically relevant materials become thermodynamically stable at high enough temperatures in spite of existing phonon instabilities. This makes the standard lattice dynamics approaches insufficient to describe stabilizing entropy effects in these materials.Solution method: We implement the Piecewise Polynomial Potential Partitioning method [1] which facilitates thermodynamic calculations in mechanically unstable materials that are stabilized at finite temperatures due to anharmonic entropy effect. The current version of our model interfaces with density functional theory code VASP [2].Additional comments including restrictions and unusual features: The P-4 code needs to be built into the ATAT toolkit [3]. The instruction on how to install P-4 into the ATAT toolkit is given in the documentation. Additional links for program files: http://go.uic.edu/p4 , https://doLorg/10.26300/zs0n-2c84.References:[1] Sara Kadkhodaei, Qi-Jun Hong, and Axel van de Walle, Free energy calculation of mechanically unstable but dynamically stabilized bcc titanium. Phys. Rev. B, 95 (2017) 064101[2] G. Kresse and J. Furthmuller, Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set. Phys. Rev. B 54 (1996) 11169[3] A. van de Walle and M. Asta and G. Ceder, The alloy theoretic automated toolkit: A user guide. Calphad 26 (2002) 539-553 (C) 2019 Elsevier B.V. All rights reserved.