Role of phonon in the thermal and electrical transports in metallic nanofilms

Abstract

Thermal rectification and phonon scattering in silicon nanofilm with cone cavity J. Appl. Phys. 112, 054312 (2012); 10.1063/1.4749394Contributions of electron and phonon transport to the thermal conductivity of GdFeCo and TbFeCo amorphous rare-earth transition-metal alloysThe electronic thermal transport in metallic nanofilms has been extensively studied. There are, however, rare reports on the influence of phonon on the thermal and electrical transports in metallic films. In the present work, equilibrium molecular dynamics with embedded-atom method is used to investigate the lattice thermal conductivity in a single-crystalline copper film. The results show that the lattice contribution to the total thermal conductivity is relatively small, nevertheless enhanced compared to that in bulk copper. The low-dimensional phonon system in metallic films is characterized by the elastic continuum model. In addition to the traditional boundary scattering, the reduced phonon group velocity and reduced Debye temperature are taken into account to discuss the finite size effect on phonon transport and electronic thermal resistivity and electrical resistivity.

Thermal properties of metallic films

“…For example, in the case of bulk cu at room temperature, the MD result in Ref. [77] of k ph = 18 W/mK is much smaller than the experimental thermal conductivity k exp = 401 W/mK, again highlighting the dominant role played by electrons in thermal transport.…”

“…For example, in Ref. [77] it was found that differences in the group velocity and also surface scattering reduced the value of k ph . Films with thickness in the range 10-30 nm were found to have k ph ~ 5-6 W/mK [77].…”

“…In Ref. [77], the MD approach was used to study Cu bulk and thin fi lms. As expected, the bulk phonon thermal conductivity is much less than the experimental thermal conductivity.…”

Grain size-induced thermo-mechanical coupling in zirconium thin films

“…Chantrenne et al [28] investigated the electron and phonon contributions on the thermal conductivity of aluminum films with a thickness range from 2 to 20 nm and found that it remarkably dropped below the bulk value. Feng et al [29] studied the in-plane thermal conductivity of nanoscale copper films and concluded that even though the lattice contribution in metallic films is enhanced compared to that in bulk metal, it is still relatively small compared to that of electrons.…”

Molecular scale analysis of dry sliding copper asperities

“…At the nano scale, the thermal transport decreases due to boundary scattering of electrons and phonons, and size effects (Yuan and Jiang 2006). Since the mean free path for electrons is larger than that of phonons, electrons suffer more scattering than phonons and therefore their contribution to thermal transport decreases (Feng et al 2009). Even then the contribution of conducting electrons is crucial in thermal transport.…”