Tunable lattice thermal conductivity of 2D MoSe2 via biaxial strain: a comparative study between the monolayer and bilayer

Strain engineering has been proved to be an effective approach to modulate various physical properties in two-dimensional (2D) materials with flexible structures. In this work, based on first-principles calculations, the impact of in-plane biaxial tensile strain on lattice thermal conductivity of bilayer MoSe 2 , involving different stacking modes, has been systematically investigated by iteratively solving phonon Boltzmann transport equation. Simultaneously, potential regulations of interfacial anharmonic effect in phonon transport via in-plane strain can also be clarified through a comparative study between the monolayer and bilayer cases. Our results indicate that thermal transport in both the monolayer and bilayer MoSe 2 is governed by low-frequency phonon branches, and the bilayer exhibits a notably reduced thermal transport capacity due to interlayer interaction existing in van der Waals homogeneous stacks. As the in-plane tensile strain is applied, a significant suppression in thermal transport capacity per layer can be further achieved in both the monolayer and bilayer cases, implying great potential for effective thermal management in 2D MoSe 2 via strain engineering. Besides, the role of homogeneous interface in phonon transport of bilayer MoSe 2 can also be regulated by the exerted in-plane tensile strain, which slows the decline in thermal conductivity with strain and leads to a larger thermal sheet conductance in the strained bilayer compared to the monolayer.