Isochoric, isobaric and ultrafast conductivities of aluminum, lithium and carbon in the warm dense matter (WDM) regime

Abstract

We study the conductivities $\sigma$ of (i) the equilibrium isochoric state (${\sigma }_{\mathrm{is}}$), (ii) the equilibrium isobaric state (${\sigma }_{\mathrm{ib}}$), and also the (iii) non-equilibrium ultrafast matter (UFM) state (${\sigma }_{\mathrm{uf}}$) with the ion temperature $T_i$ less than the the electron temperature $T_e$. Aluminum, lithium and carbon are considered, being increasingly complex warm dense matter (WDM) systems, with carbon having transient covalent bonds. First-principles calculations, i.e., neutral-pseudoatom (NPA) calculations and density-functional theory (DFT) with molecular-dynamics (MD) simulations, are compared where possible with experimental data to characterize ${\sigma }_{\mathrm{ic}},{\sigma }_{\mathrm{ib}}$ and ${\sigma }_{\mathrm{uf}}$. The NPA ${\sigma }_{\mathrm{ib}}$ are closest to the available experimental data when compared to results from DFT+MD, where simulations of about 64-125 atoms are typically used. The published conductivities for Li are reviewed and the value at a temperature of 4.5 eV is examined using supporting X-ray Thomson scattering calculations. A physical picture of the variations of $\sigma$ with temperature and density applicable to these materials is given. The insensitivity of $\sigma$ to $T_e$ below 10 eV for carbon, compared to Al and Li, is clarified.

10 figures

References in corpus (5)

• All-Electron Path Integral Monte Carlo Simulations of Warm Dense Matter: Application to Water and Carbon Plasmas
• Tetrahedral clustering in molten lithium under pressure
• An integral equation model for warm and hot dense mixtures
• Pair potentials for warm dense matter and their application to x-ray Thomson scattering in aluminum and beryllium
• A calculation of the Deuterium Hugoniot using the classical-map hypernetted-chain (CHNC) approach