Electronic contribution of Frenkel defects to thermal conductivity in body centred cubic transition metals from first-principles study.

Body centred cubic (BCC) transition metals are of high interest for nuclear applications, where they are subject to high radiation damage, which causes the material's properties to decay. Measuring the electrical and thermal properties of these materials after irradiation poses challenges due to sample size, activity, and cost of running the experiments. Traditional methods of measuring thermal properties require bulk samples. Newer measuring techniques were developed for smaller samples, but they have their limitations. Therefore, a new First Principles' method was developed to predict the electronic thermal conductivity and resistivity of Frenkel pairs (FP) in BCC transition metals. The Boltzmann Transport equation for the thermal conductivity requires the electron heat capacity, the Fermi velocity, and the electron scattering time. A model to calculate the electron-FP scattering time for point defects is shown, and extended to include the electron-phonon contributions. The electron-phonon corrections ofs-electron to thed-band from the Mott model for transition metals are presented and discussed. The method presented in this work can provide an initial insight, in the degradation of the electric and thermal properties of irradiated transition metals and their alloys, including high entropy alloys.