Thermoelectric transport properties of molybdenum fromabinitiosimulations

Abstract

We employ ab initio simulations based on density functional theory (DFT) to calculate the electronic transport coefficients (electrical conductivity, thermal conductivity, and thermopower) of molybdenum over a broad range of thermodynamic states. By comparing to available experimental data, we show that DFT is able to describe the desired transport properties of this refractory metal with high accuracy. Most noteworthy, both the positive sign and the quantitative values of the thermopower of solid molybdenum are reproduced very well. We calculate the electrical and thermal conductivity in the solid and the fluid phase between 1000 K and 20 000 K and a wide span in density and develop empirical fit formulae for direct use in practical applications, such as magnetohydrodynamics simulations. The influence of thermal expansion in conductivity measurements at constant pressure is also discussed in some detail.

Direct measurement of thermal conductivity in solid iron at planetary core conditions

“…The correction to the standard value of L determined here for ε Fe is typical for Fe at various conditions and phases 7,14,24,44 (± 30%) and is similar to other transition metals 11,45 . In Pt, L is measured 11 to deviate from the ideal value by ± 30% at temperatures up to 2,000 K. For Mo, deviations of − 10% to − 30% are predicted at high temperature 45 .…”

“…In Pt, L is measured 11 to deviate from the ideal value by ± 30% at temperatures up to 2,000 K. For Mo, deviations of − 10% to − 30% are predicted at high temperature 45 . The variation of L across transition metals at low temperature alone is large 46 , with values such as in Cu (− 9%) and W (+ 31%).…”

Conductivity of warm dense matter including electron-electron collisions

“…Furthermore, an evaluation of the Kubo formula is possible for a number of snapshots of the DFT-MD simulation; for details, see Refs. [20][21][22][23]50,51].…”

A flash heating method for measuring thermal conductivity at high pressure and temperature: Application to Pt

“…Lorenz number L for Fe at high pressure and temperature also needs to be accurately 463 determined; use of the theoretical value for a free-electron metal (Stacey and 464 Anderson, 2001;Stacey and Loper, 2007) is of questionable validity considering the 465 wide range of values seen in transition metals (French and Mattsson, 2014;Slack, 466 1964) and the proposed significance of electron-electron scattering at high 467 temperatures (Zhang et al, 2015). Measurements of Fe thermal conductivity at in-situ 468 high-pressure and temperature as well as studies on other transition metals are needed 469 to improve constraints on this important problem.…”