Observation of fast sound in metal–nonmetal transition in liquid Hg

Abstract

Liquid Hg undergoes the metal-nonmetal (M-NM) transition when it is expanded from 13.6 g cm-3 at ambient conditions to 9 g cm-3 at high temperature and high pressure. To investigate collective and single particle motions in expanded fluid Hg, we have made inelastic x-ray scattering experiments and obtained the dynamic structure factor, S(Q,ω), of fluid Hg. We analyzed S(Q,ω) within the framework of generalized hydrodynamics and found that the excitation energies of collective modes disperse three times as fast as the hydrodynamic sound velocity in the M-NM transition region at 9 gcm-3. The results indicate the existence of fast sound in expanded fluid Hg accompanying the metal-non-metal transition and strongly hint that fluctuations intrinsic to the M-NM transition are induced on atomic length scale and sub-picosecond time scale.

Computer simulation and modeling the metal to insulating transition of liquid mercury via pair, empirical, and many-body potentials

“…In short, the MC simulation of this study suggests metal to insulating transition occurs in 9.25 g/cm 3 . This result is in good agreement with both theoretically and experimentally studies [14,21,22,37] that the transition is predicted around density of 9 g/cm 3 .…”

“…1. Firstly, the overall feature of this curve coincides with previous studies [13,15,36,37,38], that manifest there is an inhomogeneous expansion. Because, the rst peak position in g(r) as nearest neighbor distance, based on three model potentials (A,B,C) mainly remains constant, while the trend of coordination number turns down.…”

Computer Simulation And Modeling The Metal To Insulating Transition Of Liquid Mercury Via Pair, Empirical And Many-Body Potentials

“…1. Firstly, The overall feature of this curve coincides with previous studies [13,15,36,37,38], that manifest there is an inhomogeneous expansion, due to the first peak position in g(r) that as nearest neighbor distance, mainly remains constant, while coordination number turn down. (molecular-like) emerges in the phase space [13], consequently, the phase transition (M-NM)…”

Future applications of the high-flux thermal neutron spectroscopy: the ever-green case of collective excitations in liquid metals

“…As a final remark, the complex dynamics of Hg close to the metal to insulator transition has also been investigated in [169,170] by x-ray scattering. It would be extremely important to carry out further neutron studies, coherent and incoherent, of this challenging topic, despite the extreme conditions of the measurements that require improved instrumentation at the new sources.…”