First-principles calculations of thermal transport properties in MoS2/MoSe2 bilayer heterostructure

Abstract

Bilayer transition metal dichalcogenide heterostructures obtained by vertical stacking have attracted considerable attention because of their potential applications in thermoelectric and optoelectronics devices. The thermal transport behavior plays a pivotal role in assessing their functional performance. Here, we systematically investigate the thermal transport properties of the MoS₂/MoSe₂ bilayer heterostructure (MoS₂/MoSe₂-BH) by combining first-principles calculations and Boltzmann transport theory (BTE). The results show that the thermal conductivity of MoS₂/MoSe₂-BH at room temperature is 25.39 W m⁻¹ K⁻¹, which is in-between those of monolayer MoSe₂ and MoS₂. According to our calculated orbital-resolved phonon dispersion curves, Grüneisen parameters, phonon group velocity and relaxation time, we find that the acoustic and low-frequency optical branches below 172.65 cm⁻¹ have strong coupling and contribute mainly to the lattice thermal conductivity. Compared with free standing monolayer MoS₂ and MoSe₂, the lattice thermal conductivity of MoS₂/MoSe₂-BH is influenced by the weak van der Waals interlayer interactions.