A Search for Two Types of Transverse Excitations in Liquid Polyvalent Metals at Ambient Pressure: An Ab Initio Molecular Dynamics Study of Collective Excitations in Liquid Al, Tl, and Ni

Frontiers in Physics

Wax, Jean-Franç¹  Jakse, Noë²  Bryk, Taras²  Demchuk, Taras³  l⁴ 

[1] Grenoble Alpes, Centre National de la Recherche Scientifique, Grenoble INP, SIMaP, France;Institute for Condensed Matter Physics of the National Academy of Sciences of Ukraine, Ukraine;Lviv Polytechnic National University, Ukraine;Université

关键词: liquid metals;    collective dynamics;    Collective excitations;    ab initio calculations;    Molecular Dynamics Simulation;   

DOI  :  10.3389/fphy.2018.00006

学科分类：物理（综合）

来源: Frontiers

【 摘 要 】

Recent findings of pressure-induced emergence of unusual high-frequency contribution to transverse current spectral functions in several simple liquid metals at high pressures raised a question whether similar features can be observed in liquid metals at ambient conditions. We report here analysis of ab initio molecular dynamics-derived longitudinal (L) and transverse (T) current spectral functions and corresponding dispersions of collective excitations in liquid polyvalent metals Al, Tl, Ni. We have not found evidences of the second branch of high-frequency transverse modes in liquid Al and Ni, while in the case of liquid Tl they were clearly present in transverse dynamics. The vibrational density of states for liquid Tl has a pronounced high-frequency shoulder, which is located right in the frequency range of the second high-frequency transverse branch, while for liquid Al and Ni the vibrational density of states has only a weak indication of possible high-frequency shoulder. The origin of specific behavior of transverse excitations in liquid Tl is discussed.

【 授权许可】

CC BY