Probing local heating and cooling at interfaces: a non-equilibrium Green's function study

Interface electrical resistance is a well-known phenomenon that leads to heating at interface. Yet, it is not clear where the heating exactly happens. Knowing where heating happens is particularly important for nanodevices, especially considering that at the interfaces, there is also an interfacial thermal resistance. Pinpointing where heat is dissipated is essential for determining the temperature drop caused by interfacial thermal resistance. To answer this question, we employ non-equilibrium Green's function calculation. In particular, the electron-phonon interaction is introduced through Büttiker probes. The electron-phonon scattering rates are obtained from electron-phonon Wannier interpolation on a very fine mesh. With our parameter-free model, we are able to calculate spatially varying energy flux and probe the local heating and cooling. Our calculation helps reveal electron behaviors across interface and improve the design of nanodevices.