Effect of interlayer on interfacial thermal transport and hot electron cooling in metal-dielectric systems: An electron-phonon coupling perspective

It was reported that an interlayer with intermediate phonon spectra between two dielectric materials could reduce the phononic interfacial thermal resistance. In this work, we show that an appropriate choice of interlayer materials with relatively strong electron-phonon coupling could significantly enhance interfacial thermal transport across metal-dielectric interfaces. Our Boltzmann transport simulations demonstrate that such enhancement is achieved by the elimination of electron-phonon nonequilibrium near the original metal-dielectric interface. Moreover, we reveal that interlayer can substantially accelerate hot electron cooling in thin films with weak electron-phonon coupling, for example, Cu, Ag, and Au, supported on a dielectric substrate. At the same time, lattice heating in the thin film is largely reduced.