skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Electron-phonon coupling mechanisms for hydrogen-rich metals at high pressure

; ;
Publication Date:
Sponsoring Org.:
OSTI Identifier:
Grant/Contract Number:
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 96; Journal Issue: 10; Related Information: CHORUS Timestamp: 2017-09-11 10:17:04; Journal ID: ISSN 2469-9950
American Physical Society
Country of Publication:
United States

Citation Formats

Tanaka, K., Tse, J. S., and Liu, H. Electron-phonon coupling mechanisms for hydrogen-rich metals at high pressure. United States: N. p., 2017. Web. doi:10.1103/PhysRevB.96.100502.
Tanaka, K., Tse, J. S., & Liu, H. Electron-phonon coupling mechanisms for hydrogen-rich metals at high pressure. United States. doi:10.1103/PhysRevB.96.100502.
Tanaka, K., Tse, J. S., and Liu, H. 2017. "Electron-phonon coupling mechanisms for hydrogen-rich metals at high pressure". United States. doi:10.1103/PhysRevB.96.100502.
title = {Electron-phonon coupling mechanisms for hydrogen-rich metals at high pressure},
author = {Tanaka, K. and Tse, J. S. and Liu, H.},
abstractNote = {},
doi = {10.1103/PhysRevB.96.100502},
journal = {Physical Review B},
number = 10,
volume = 96,
place = {United States},
year = 2017,
month = 9

Journal Article:
Free Publicly Available Full Text
This content will become publicly available on September 11, 2018
Publisher's Accepted Manuscript

Citation Metrics:
Cited by: 2works
Citation information provided by
Web of Science

Save / Share:
  • The dependence of the strength of the electron-phonon coupling and the electron heat capacity on the electron temperature is investigated for eight representative metals, Al, Cu, Ag, Au, Ni, Pt, W, and Ti, for the conditions of strong electron-phonon nonequilibrium. These conditions are characteristic of metal targets subjected to energetic ion bombardment or short-pulse laser irradiation. Computational analysis based on first-principles electronic structure calculations of the electron density of states predicts large deviations (up to an order of magnitude) from the commonly used approximations of linear temperature dependence of the electron heat capacity and a constant electron-phonon coupling. These thermophysicalmore » properties are found to be very sensitive to details of the electronic structure of the material. The strength of the electron-phonon coupling can either increase (Al, Au, Ag, Cu, and W), decrease (Ni and Pt), or exhibit nonmonotonic changes (Ti) with increasing electron temperature. The electron heat capacity can exhibit either positive (Au, Ag, Cu, and W) or negative (Ni and Pt) deviations from the linear temperature dependence. The large variations of the thermophysical properties, revealed in this work for the range of electron temperatures typically realized in femtosecond laser material processing applications, have important implications for quantitative computational analysis of ultrafast processes associated with laser interaction with metals.« less
  • On the basis of the crystal structures of ..beta..-(ET)/sub 2/X (X/sup -/ = IBr/sub 2//sup -/, AuI/sub 2//sup -/, I/sub 3//sup -/) determined at low temperature under ambient and applied pressure, they examined the structural factors responsible for the occurrence of the structural modulation in ..beta..-(ET)/sub 2/I/sub 3/ under ambient pressure, its disappearance under pressure greater than approx. 0.5 kbar, and its effect on the superconducting transition temperature T/sub c/ and the dependence of T/sub c/ on anion X/sup -/ in ..beta..-(ET)/sub 2/X. ET is an abbreviation for BEDT-TTF, i.e., bis(ethylenedithio)tetrathiafulvalene. The electron-phonon coupling constants, lambda, calculated for ..beta..-(ET)/sub 2/Xmore » on the basis of the McMillan equation suggest that the lattice softness with respect to translational and/or librational modes of vibration increases in the order ..beta..-(ET)/sub 2/I/sub 3/ < ..beta..-(ET)/sub 2/IBr/sub 2/ < ..beta..-(ET)/sub 2/AuI/sub 2/ < ..beta..*-(ET)/sub 2/I/sub 3/, where ..beta..*-(ET)/sub 2/I/sub 3/ refers to the ..beta..-(ET)/sub 2/I/sub 3/ salt under an applied pressure greater than approx. 0.5 kbar with T/sub c/ similarly ordered 8 K. They also discuss the importance of hydrogen...anion interactions in understanding the lower T/sub c/ values (1-1.5 K) of the other class of organic superconductors (TMTSF)/sub 2/X (X/sup -/ = ClO/sub 4//sup -/, PF/sub 6//sup -/) compared to the ..beta..-(ET)/sub 2/X systems and the implications concerning the synthesis of new organic superconductors.« less
  • Metals exposed to ultrafast laser irradiation close to ablative regimes show often a submicron-scale (near 0.5 {mu}m) periodic organization of the surface as ripples. Using two classes of metallic materials (transition and noble), we have determined that the ripples amplitude is strongly correlated to the material transport properties, namely electron-phonon relaxation strength, electronic diffusion, and to the energy band characteristics of the electronic laser excitation. This particularly depends on the topology of the electronic structure, including d-band effects on electronic excitation. Comparing the effects of electron-phonon nonequilibrium lifetimes for the different metals under similar irradiation conditions, we indicate how themore » electron-phonon coupling strength affects the electronic thermal diffusion, the speed of phase transformation and impacts on the ripples contrast. The highest contrast is observed for ruthenium, where the electron-phonon coupling is the strongest, followed by tungsten, nickel, and copper, the latter with the least visible contrast. The dependence of surface patterns contrast with fluence is linked to the dependence of the relaxation characteristics with the electronic temperature.« less
  • We study the scattering mechanisms driving electron-phonon relaxation in thin gold films via pump-probe time-domain thermoreflectance. Electron-electron scattering can enhance the effective rate of electron-phonon relaxation when the electrons are out of equilibrium with the phonons. In order to correctly and consistently infer electron-phonon coupling factors in films on different substrates, we must account for the increase in steady-state lattice temperature due to laser heating. Our data provide evidence that a thermalized electron population will not directly exchange energy with the substrate during electron-phonon relaxation, whereas this pathway can exist between a non-equilibrium distribution of electrons and a non-metallic substrate.
  • No abstract prepared.