Validation of the Wiedemann-Franz Law in Solid and Molten Tungsten above 2000 K through Thermal Conductivity Measurements via Steady-State Temperature Differential Radiometry

We measure the thermal conductivity of solid and molten tungsten using steady state temperature differential radiometry. We demonstrate that the thermal conductivity can be well described by application of Wiedemann-Franz law to electrical resistivity data, thus suggesting the validity of Wiedemann-Franz law to capture the electronic thermal conductivity of metals in their molten phase. We further support this conclusion using ab initio molecular dynamics simulations with a machine-learned potential. Our results show that at these high temperatures, the vibrational contribution to thermal conductivity is negligible compared to the electronic component.Received 7 September 2023Revised 11 January 2024Accepted 26 January 2024DOI:https://doi.org/10.1103/PhysRevLett.132.146303Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasLattice thermal conductivityThermal conductivityPhysical SystemsLiquid metalsMetalsTechniquesDensity functional theoryLaser techniquesMachine learningThermometryCondensed Matter, Materials & Applied Physics