arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1308.1024cond-mat.mtrl-sci
收藏

SrRuO $_3$结构和弹性性质的第一性原理研究

A first-principles study of structural and elastic properties of bulk SrRuO$_3$

Š. Masys, V. Jonauskas

摘要:

我们提出了一个第一性原理调查的结构和弹性性能的实验观察相的散装SrRuO $_3$ -即正交晶系,四方晶系,立方晶系-通过应用密度泛函理论(DFT)近似。首先,我们把注意力集中在计算的晶格常数的准确性,以找出DFT方法,最好地代表SrRuO $_3$的晶体结构,因为许多重要的物理量至关重要地依赖于体积的变化。接下来,我们评估单晶体的弹性常数,机械稳定性,宏观弹性参数,试图至少部分地弥补现有的缺乏这些基本功能的SrRuO $_3$的信息。最后分析了低温正交相在$C_{44}$相关剪切变形下的反常行为。结果表明,在临界应变值下,系统表现出明显偏离初始行为,导致等对称相变。此外,在$C_{44}$相关的剪切变形下,四相SrRuO 3变得机械不稳定,这引起了一个悬而未决的问题,即是什么使其在高温下实验上可观察到。

英文摘要:

We present a first-principles investigation of structural and elastic properties of experimentally observed phases of bulk SrRuO$_3$ - namely orthorhombic, tetragonal, and cubic - by applying density functional theory (DFT) approximations. At first, we focus our attention on the accuracy of calculated lattice constants in order to find out DFT approaches that best represent the crystalline structure of SrRuO$_3$, since many important physical quantities crucially depend on change in volume. Next, we evaluate single-crystal elastic constants, mechanical stability, and macroscopic elastic parameters trying to at least partially compensate for the existing lack of information about these fundamental features of SrRuO$_3$. Finally, we analyze the anomalous behavior of low-temperature orthorhombic phase under $C_{44}$ related shear deformation. It turns out that at critical strain values the system exhibits a distinct deviation from the initial behavior which results in an isosymmetric phase transition. Moreover, under $C_{44}$ related shear deformation tetragonal SrRuO3 becomes mechanically unstable raising an open question of what makes it experimentally observable at high temperatures.

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。

↑