论文标题
准确预测化学短距离顺序及其对无序合金热力学，结构和电子特性的影响：以Cu $ _ {3} $ AU为例
Accurate prediction of chemical short-range order and its effect on thermodynamic, structural, and electronic properties of disordered alloys: exemplified in Cu$_{3}$Au
论文作者
论文摘要
基于密度功能理论（DFT）的电子结构方法用于直接量化化学短距离顺序（SRO）对原型面部中心型（FCC）CU $ _ {3} $ AU Alloy的热力学，结构和电子特性的影响。我们表明，可以调节SRO以更改键合和晶格动力学（即声子），并详细介绍如何使用SRO更改这些属性。热力学上有利的SRO从-0.0343 EV-ATOM $^{ - 1} $ to -0.0682 EV-ATOM $^{ - 1} $提高了Cu $ _ {3} $ au的相位稳定性。我们使用基于DFT的线性响应理论来预测SRO及其电子起源，并准确估计过渡温度，排序不稳定性（L1 $ _2 $）和Warren-Cowley SRO参数，在实验中观察到。对真实空间SRO的准确预测可以优先于计算和资源密集型方法，例如蒙特卡罗方法或实验，这将通过为超级分子提供优化的SRO来实现大型分子动态模拟。我们还分析了声子分散并估算Cu $ _ {3} $ au的振动熵变化（从9k $ _ {b} $ 300 k at 300 k到6 $ k_ {b} $ 100 k）。我们从SRO分析中确定，化学相互作用的排除可能会导致化学复杂合金中真实性质的偏差。此处描述的第一原理方法适用于任何任意的复杂固体合金，包括多元元素合金，因此对设计具有技术有用的材料有希望。
Electronic-structure methods based on density-functional theory (DFT) were used to directly quantify the effect of chemical short-range order (SRO) on thermodynamic, structural, and electronic properties of archetypal face-centered-cubic (fcc) Cu$_{3}$Au alloy. We show that SRO can be tuned to alter bonding and lattice dynamics (i.e., phonons) and detail how these properties are changed with SRO. Thermodynamically favorable SRO improves phase stability of Cu$_{3}$Au from -0.0343 eV-atom$^{-1}$ to -0.0682 eV-atom$^{-1}$. We use DFT-based linear-response theory to predict SRO and its electronic origin, and accurately estimate the transition temperature, ordering instability (L1$_2$), and Warren-Cowley SRO parameters, observed in experiments. The accurate prediction of real-space SRO gives an edge over computationally and resource intensive approaches such as Monte-Carlo methods or experiments, which will enable large-scale molecular dynamic simulations by providing supercells with optimized SRO. We also analyze phonon dispersion and estimate the vibrational entropy changes in Cu$_{3}$Au (from 9k$_{B}$ at 300 K to 6$k_{B}$ at 100 K). We establish from SRO analysis that exclusion of chemical interactions may lead to a skewed view of true properties in chemically complex alloys. The first-principles methods described here are applicable to any arbitrary complex solid-solution alloys, including multi-principal-element alloys, so hold promise for designing technologically useful materials.
