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

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.