Role of dipole engineering in in-plane phonon thermal transport of BlueP/MXY (M = Mo, W; X/Y = S, Se) van der Waals heterostructures

Dipole engineering serves as a crucial non-destructive approach for modulating the electronic properties and interfacial coupling in two-dimensional layered materials and heterostructures. Here, the modulation of electronic properties and phonon transport in BlueP/MXY (M = Mo, W; X/Y = S, Se) heterostructures via dipole engineering is systematically investigated. We quantitatively evaluate the in-plane thermal conductivity to elucidate the role of dipole moment coupling, which is intrinsically controlled by the stacking order. Among the optical phonons, modes with interlayer vibrational characteristics (shear modes) are the dominant contributors to the in-plane thermal conductivity. Their overall contribution is important, ranking second only to that of the three acoustic phonon modes. Interestingly, dipole moment coupling governs the interlayer charge transfer, a mechanism that gives rise to the variations in phonon anharmonicity observed for different stacking orders. This work presents a paradigm for the manipulation of thermal transport in vdW heterostructures enabled by dipole engineering, which is of great significance for physical and engineering applications, including electronics, thermoelectrics, and thermal management.