Decompose the electron and phonon thermal transport of intermetallic compounds NiAl and Ni3Al by first-principles calculations

Abstract

In order to develop a better understanding of the thermal conduction of the intermetallic compounds NiAl and Ni3Al, detailed electron-phonon scattering was investigated by first-principles calculations. The phonon thermal conductivity of NiAl and Ni3Al was calculated by considering phonon-phonon and electron-phonon scatterings. It is found that electron-phonon coupling has a strong effect on the phonon thermal conductivity. At a temperature of 100K, the electron-phonon coupling will induce 55% and 75% reduction in phonon thermal conductivity of NiAl and Ni3Al, respectively. Such an effect decreases with increasing temperature. The electron thermal conductivity was also predicted by considering electron-phonon scattering. We find that though the electrons dominate the thermal transport in NiAl and Ni3Al at high temperatures, the phonons have significant contribution to the total thermal conductivity in the sub-room temperature range. Moreover, we find that at room temperature phonons with mean free paths between 1 and 100nm are the dominant contributors to the thermal conductivity, while the mean free paths of dominant electrons are 1–20nm.