Monserrat Bartomeu
Department of Physics and Astronomy, Rutgers University, Piscataway, NJ 08854-8019, United States of America. TCM Group, Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom.
J Phys Condens Matter. 2018 Feb 28;30(8):083001. doi: 10.1088/1361-648X/aaa737.
The interaction between electrons and phonons underlies multiple phenomena in physics, chemistry, and materials science. Examples include superconductivity, electronic transport, and the temperature dependence of optical spectra. A first-principles description of electron-phonon coupling enables the study of the above phenomena with accuracy and material specificity, which can be used to understand experiments and to predict novel effects and functionality. In this topical review, we describe the first-principles calculation of electron-phonon coupling from finite differences. The finite differences approach provides several advantages compared to alternative methods, in particular (i) any underlying electronic structure method can be used, and (ii) terms beyond the lowest order in the electron-phonon interaction can be readily incorporated. But these advantages are associated with a large computational cost that has until recently prevented the widespread adoption of this method. We describe some recent advances, including nondiagonal supercells and thermal lines, that resolve these difficulties, and make the calculation of electron-phonon coupling from finite differences a powerful tool. We review multiple applications of the calculation of electron-phonon coupling from finite differences, including the temperature dependence of optical spectra, superconductivity, charge transport, and the role of defects in semiconductors. These examples illustrate the advantages of finite differences, with cases where semilocal density functional theory is not appropriate for the calculation of electron-phonon coupling and many-body methods such as the GW approximation are required, as well as examples in which higher-order terms in the electron-phonon interaction are essential for an accurate description of the relevant phenomena. We expect that the finite difference approach will play a central role in future studies of the electron-phonon interaction.
电子与声子之间的相互作用是物理、化学和材料科学中多种现象的基础。例子包括超导性、电子输运以及光谱的温度依赖性。电子 - 声子耦合的第一性原理描述能够精确且针对具体材料地研究上述现象，可用于理解实验并预测新的效应和功能。在这篇专题综述中，我们描述了基于有限差分法的电子 - 声子耦合的第一性原理计算。与其他方法相比，有限差分法具有几个优点，特别是：（i）可以使用任何底层的电子结构方法；（ii）电子 - 声子相互作用中最低阶以外的项可以很容易地纳入。但这些优点伴随着巨大的计算成本，直到最近这一直阻碍了该方法的广泛应用。我们描述了一些近期的进展，包括非对角超胞和热线法，这些进展解决了这些困难，并使基于有限差分法的电子 - 声子耦合计算成为一个强大的工具。我们回顾了基于有限差分法的电子 - 声子耦合计算的多种应用，包括光谱的温度依赖性、超导性、电荷输运以及缺陷在半导体中的作用。这些例子说明了有限差分法的优点，包括半局域密度泛函理论不适用于电子 - 声子耦合计算而需要诸如GW近似等多体方法的情况，以及电子 - 声子相互作用中的高阶项对于准确描述相关现象至关重要的例子。我们预计有限差分法将在未来电子 - 声子相互作用的研究中发挥核心作用。
