Ray-tracing Monte Carlo model of electronic thermal conductivity in single-crystal tungsten alloys

In this work, we present a discrete ray-tracing Monte Carlo approach to simulate electron dynamics in the presence of a thermal gradient to calculate the thermal conductivity in W and W-Re alloys. The model generates and tracks electron trajectories in the conduction band with probabilities and energies dictated by Fermi-Dirac statistics. Electron dynamics follows from a set of discrete low-energy scattering processes for metals partic- ularized for W and W-Re systems. A directional heat flux is then obtained from the difference between the number of electrons exiting through the cold end and those exiting through the hot end. We demonstrate that this heat flux scales precisely with the applied thermal gradient, leading to self-consistent values of the thermal conductivity regardless of the prescribed temperature gradient. Our model lacks any adjustable parameters and is in good general agreement with experimental measurements in single crystal W and W-Re. However, our calculations overpredict the temperature dependence of the thermal conductivity at high temperatures, a fact which we attribute to the lack of lattice thermal conduction in the present work.