Anharmonic lattice dynamics via the special displacement method
Anharmonic lattice dynamics via the special displacement method
复制标题
DOI：
10.1103/physrevb.108.035155
复制
发表时间：
2022-12
影响因子：
3.7
通讯作者：
M. Zacharias;G. Volonakis;F. Giustino;J. Even
中科院分区：
文献类型：
--
作者：
M. Zacharias;G. Volonakis;F. Giustino;J. Even
基于自洽声子理论和特殊位移法，我们发展了一种处理固体中非谐性的方法。我们表明，这种方法能够有效地计算与温度相关的非谐声子色散，只需很少的步骤就可以实现系统自由能的最小化。在具有多势能面的强非简谐材料中，如立方的SrTiO$3$、CsPbBr3$、CsPbI$3$、CsSnI$3$和Zr，我们展示了这种方法。我们的结果与实验和以前基于随机非微扰和分子动力学模拟的第一性原理研究相一致。我们以多态基态的简谐声子为起点，通过迭代混合动力学矩阵，实现了一种非常健壮的工作流程。我们还认为，多态基态的声子可能为探索非谐性提供了一个很好的初始近似。考虑到本方法的简单性、有效性和稳定性，它特别适用于任何电子结构代码和研究强非谐系统中的电子-声子耦合。
On the basis of the self-consistent phonon theory and the special displacement method, we develop an approach for the treatment of anharmonicity in solids. We show that this approach enables the efficient calculation of temperature-dependent anharmonic phonon dispersions, requiring very few steps to achieve minimization of the system's free energy. We demonstrate this methodology in the regime of strongly anharmonic materials which exhibit a multi-well potential energy surface, like cubic SrTiO$_3$, CsPbBr$_3$, CsPbI$_3$, CsSnI$_3$, and Zr. Our results are in good agreement with experiments and previous first-principles studies relying on stochastic nonperturbative and molecular dynamics simulations. We achieve a very robust workflow by using harmonic phonons of the polymorphous ground state as the starting point and an iterative mixing scheme of the dynamical matrix. We also suggest that the phonons of the polymorphous ground state might provide an excellent starting approximation to explore anharmonicity. Given the simplicity, efficiency, and stability of the present treatment to anharmonicity, it is especially suitable for use with any electronic structure code and for investigating electron-phonon couplings in strongly anharmonic systems.