论文标题
通过特殊位移方法的Anharmonic晶格动力学
Anharmonic lattice dynamics via the special displacement method
论文作者
论文摘要
在自洽的声子理论和特殊位移方法的基础上，我们开发了一种治疗固体过度性的方法。我们表明，这种方法可以有效地计算温度依赖性的Anharmonic声子分散，需要几步措施才能最小化系统的自由能。我们在强烈的静脉材料的制度中演示了这种方法，这些材料表现出多孔势能表面，例如立方srtio $ _3 $，CSPBBR $ _3 $，CSPBI $ _3 $，CSSSNI $ _3 $和ZR和ZR。我们的结果与实验和以前的第一原理研究非常吻合，该研究依赖于随机非扰动和分子动力学模拟。我们通过使用多态基态的谐波声子作为动力矩阵的起点和迭代混合方案来实现非常强大的工作流程。我们还建议多态基态的声子可能会提供出色的启动近似，以探索非谐度。鉴于本处理对非谐度的简单性，效率和稳定性，它特别适合与任何电子结构代码一起使用，并用于在强烈的弹药系统中调查电子 - 音波耦合。
On the basis of the self-consistent phonon theory and the special displacement method, we develop an approach for the treatment of anharmonicity in solids. We show that this approach enables the efficient calculation of temperature-dependent anharmonic phonon dispersions, requiring very few steps to achieve minimization of the system's free energy. We demonstrate this methodology in the regime of strongly anharmonic materials which exhibit a multi-well potential energy surface, like cubic SrTiO$_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.
