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EST综述|The physical significance of imaginary phonon modes in crystals

13 1月 2023 gabriels

The lattice vibrations (phonon modes) of crystals underpin a large number of material properties. The harmonic phonon spectrum of a solid is the simplest description of its structural dynamics and can be straightforwardly derived from the Hellman–Feynman forces obtained in a ground-state electronic structure calculation. The presence of imaginary harmonic modes in the spectrum indicates that a structure is not a local minimum on the structural potential-energy surface and is instead a saddle point or a hilltop, for example. This can in turn yield important insight into the fundamental nature and physical properties of a material. In this review article, we discuss the physical significance of imaginary harmonic modes and distinguish between cases where imaginary modes are indicative of such phenomena, and those where they reflect technical problems in the calculations. We outline basic approaches for exploring and renormalising imaginary modes, and demonstrate their utility through a set of three case studies in the materials sciences.

文章介绍

The physical significance of imaginary phonon modes in crystals

Ioanna Pallikara, Prakriti Kayastha, Jonathan M Skelton and Lucy D Whalley

通讯作者：

Jonathan M Skelton，英国曼彻斯特大学
Lucy D Whalley，英国诺森比亚大学

期刊介绍

Electronic Structure

Electronic Structure（EST）是一本新发表的多学科期刊，覆盖电子结构研究的理论和实验工作，包括新方法的开发。EST是第一本致力于服务电子结构领域的期刊，涵盖材料学、物理学、化学和生物学。除了原创性研究外，EST还发表专题综述、专刊和技术笔记。