论文标题
在升高温度下钙棍蛋白酶的动态稳定：立方bafeo $ _ {\ textbf {3}} $与空位订购的单斜bafeo $ _ {\ textbf {\ textbf {2.67}} $之间的比较
Dynamic stabilization of perovskites at elevated temperatures: A comparison between cubic BaFeO$_{\textbf{3}}$ and vacancy-ordered monoclinic BaFeO$_{\textbf{2.67}}$
论文作者
论文摘要
在$ \ textit {ab initio} $框架下研究了有序职位空缺对perovskites动态稳定性的影响，重点关注立方bafeo $ _ {3} $（$ pm \ bar \ bar {3} m $）和空置的莫诺克林订购的monoclinic bafeo bafeo $ $ $ _ {2.67} $ {$ {$ {$ p2 $ {$ p2 n。谐波近似表明，这两种结构在0 K处动态不稳定。对于单斜结构，不稳定性与有序空位附近的四面体相协调四面体的旋转扭曲有关。 $ \ textit {ab intib} $分子动力学模拟与引入的结构描述符结合表明，这两种结构都稳定在130 K以上。我们的结果表明，有序的空缺并没有显着改变BA $ - $ $ $ fe $ - $ fe $ - $ o-o o perovskites的关键温度。此外，在有序空位附近的O阴离子的轨迹的显着不对称揭示了高于其临界温度的空缺结构的强大非谐度。
The impact of ordered vacancies on the dynamic stability of perovskites is investigated under the $\textit{ab initio}$ framework with a focus on cubic BaFeO$_{3}$ ($Pm\bar{3}m$) and vacancy-ordered monoclinic BaFeO$_{2.67}$ ($P2_{1}/m$). The harmonic approximation shows that both structures are dynamically unstable at 0 K. For the monoclinic structure, the instability is related to rotational distortions of the Fe coordination tetrahedra near the ordered vacancies. $\textit{Ab initio}$ molecular dynamics simulations in combination with the introduced structural descriptor demonstrate that both structures are stabilized above 130 K. Our results suggest that the ordered vacancies do not significantly alter the critical temperature at which Ba$-$Fe$-$O perovskites are dynamically stabilized. Further, strong anharmonicity for the vacancy-ordered structure above its critical temperature is revealed by a significant asymmetry of the trajectories of O anions near the ordered vacancies.
