Decompose the electron and phonon thermal transport of intermetallic compounds NiAl and Ni_3Al by first-principles calculations

摘要

In order to develop a better understanding of the thermal conduction of the intermetallic compounds NiAl and Ni_3Al, detailed electron-phonon scattering was investigated by first-principles calculations. The phonon thermal conductivity of NiAl and NJ_3Al 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 100 K, the electron-phonon coupling will induce 55% and 75% reduction in phonon thermal conductivity of NiAl and Ni_3Al, 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 N1_3Al 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 1-20 nm.