Unveiling inelastic phonon scattering at Al-Al2O3 interfaces by machine-learning molecular dynamics

The temperature dependence of interfacial thermal conductance (ITC) of metal/oxide interfaces and the underlying inelastic phonon scattering mechanism remains a controversy. In this work, we investigate heat transport across Al/Al2O3 interface by nonequilibrium molecular dynamics (NEMD) simulations with neuroevolution potentials trained on first-principles calculations. Our NEMD simulation results with quantum correction agree well with the experimentally inferred phonon-mediated ITC of atomically sharp interface below room temperature. We demonstrate decisive evidence of significant inelastic phonon scattering by both the temperature-dependent ITC and delicate spectral analysis. In addition, we discuss a way to fill the gap between the predicted increasing ITC by NEMD and the experimentally observed saturation at elevated temperatures. This work thus advances the fundamental understanding of thermal transport across metal/oxide interfaces and highlights the critical role of atomic-scale interfacial structure in dictating the microscopic scattering mechanism.