Role of modification interlayers in enhancing thermal transport across metal/diamond interfaces

Abstract Metal–diamond composite materials are acknowledged as promising high-thermal-conductivity candidates for electronic cooling and energy transfer, offering tunable properties and competitive cost. However, their performance is significantly limited by the poor metal/diamond interfacial thermal conductance (ITC). Many theoretical and experimental studies have highlighted the benefits of modification interlayers at metal/diamond interfaces, but the underlying phonon-level mechanisms remain unclear. Here, we focus on the widely used Cu/diamond heterostructure and reveal how a nanometric Ti interlayer augments interfacial thermal transport. Leveraging lattice dynamics simulations driven by a specifically trained MACE potential model, we demonstrate that an atomically flat Ti interlayer enhances the ITC by ∼32% compared to the bare Cu/diamond interface. Spectral and mode-resolved phonon analyses further reveal that additional channels for phonon transmission can be established by introducing the Ti interlayer, particularly for phonons with wavevector near the Γ – X direction. These insights help clarify the role of modification interlayers on tuning heat transfer across metal/diamond interfaces and provide guidelines for upgrading the thermal performance of metal–diamond composites.