Weak Interfacial Coupling Effect on In-Plane Thermal Conductivity of BoronP/JTMD van der Waals Heterostructures

Dipole engineering based on Janus transition metal dichalcogenides (JTMD) is a crucial approach to modulate the interfacial electronic properties, yet the impact of stacking-order-driven dipole engineering on phonon transport remains unclear. We investigated theoretically the effect of weak interface coupling on in-plane phonon transport by introducing stacking orders for vdW heterostructures constructed by boron phosphide (BoronP) and a JTMD monolayer. The thermal conductivity of BoronP/JTMD heterostructures is nearly one-fifth that of the BoronP monolayer, resulting from weak interfacial interactions mediated by more phonon scattering channels and anharmonicity. Beyond that, phonon transport properties of BoronP/JTMD heterostructures exhibit a certain sensitivity to altering stacking order, in addition to the already understood electron structure. Beyond, the contribution of optical phonon modes to thermal conductivity should not be neglected in the studied system, as the vibrational modes that make significant contributions to thermal conductivity exhibit characteristics of interfacial coupling (e.g., interlayer breathing mode and interlayer shear mode). This study highlights the importance of introducing phonon transport mechanisms into interface coupling design and optimization, laying a theoretical foundation for innovative strategies to handle the thermal transport phenomenon in nanoelectronic devices.