Unraveling interfacial thermal transport in β-Ga2O3/h-BN van der Waals heterostructures

As global power consumption rapidly increases with generation of significant amount of heat, efficient thermal management in electronic equipments becomes an urgent task, which requires a comprehensive understanding on thermal transport in heterostructures within devices. Here, we present detailed examination on the interfacial thermal transport of van der Waals (vdW) heterostructures, composed of β-Ga₂O₃ and hexagonal boron nitride (h-BN) multilayers. Through extensive molecular dynamics simulations, we show that the interfacial thermal conductance (ITC) of β-Ga₂O₃/h-BN system becomes as high as 136.8MWm⁻²K⁻¹, and the high ITC value results from substantial phonon interaction across the interface. In addition to the pristine interface, the effect of structural modulation including strain, vacancies and substitutional defects in h-BN multilayers on the ITC is also analyzed, and it is demonstrated that there exists ranges of strain values and defect concentrations which increase the ITC, and that the enhanced ITC is the result of the interplay among the interfacial distance, the overlap in the phonon density of states and elastic mismatch between β-Ga₂O₃ and h-BN multilayers. These results not only provide insights into understanding interfacial phonon transport in vdW systems but also offer guiding principles for designing efficient heat dissipators in device applications.