Cu/GaN heterointerfaces exist widely in electronic devices and constitute one of the primary thermal resistances. The intricate interfacial morphology and electron-phonon coupling effects pose significant challenges to the modeling of interfacial thermal transport. In this study, an advanced electron density–corrected two-temperature molecular dynamics (EDC-TTMD) framework combined with a fractal rough interface was developed to accurately capture electron-phonon coupling behaviors at rough interfaces. The model was first validated by available experimental data of three types of heterojunctions—Cu/diamond, Cu/BN, and Al/GaN. The thermal boundary conductance (TBC) predicted by present EDC-TTMD agrees more with experimental data than the nonequilibrium molecular dynamics results. Subsequently, Cu/GaN heterojunctions with various interfacial roughnesses were constructed and simulated. The results reveal that the TBC undergoes a rapid increase as the interfacial roughness increases and then decreases gradually after reaching a plateau. Finally, based on the thermal resistance analysis and phonon structure calculations, the enhancement of TBC at low interfacial roughness is primarily attributed to the introduction of electron-phonon transport channels, which was neglected in previous simulations. In contrast, the slight reduction in TBC at high interfacial roughness is primarily attributed to the enhanced phonon localization and interfacial scattering. This study establishes a novel framework for simulating electron-phonon coupled nonequilibrium thermal transport across metal/semiconductor heterojunctions with rough interfaces, providing insights into the regulation of thermal boundary conductance in such systems.

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• Heat transfer
• Interface & surface thermodynamics
• Lattice thermal conductivity
• Solid-solid interfaces
• Molecular dynamics