Two-dimensional MoS_2-MoSe_2 lateral superlattice with minimized lattice thermal conductivity

摘要

Single-layer transition metal dichalcogenides (TMDCs) are showing promising thermoelectric applications due to their superior stability and electronic transport properties. Unfortunately, the intrinsic high lattice thermal conductivity prevents their further improvement of thermoelectric performance. Motivated by recent experimental synthesis of two-dimensional TMDC heterostructures and superlattices, we propose to minimize the lattice thermal conductivity of single-layer MoS2 and MoSe2 using the lateral superlattice (LS) as building blocks. First-principles calculations with the phonon Boltzmann transport equation reveal a remarkably low lattice thermal conductivity of MoS2-MoSe2 LS due to the enhanced anharmonic phonon scattering as compared to the individual single-layer. We also show that the strong phonon anisotropy of MoS2-MoSe2 LS is primarily ascribed to the out-of-plane quadratic acoustic branch and orientation-dependent anharmonic scattering. Our calculations clearly demonstrate the advantages of LS structure in minimizing the lattice thermal conductivity of single-layer TMDCs and also accelerate their related applications in the field of renewable energy. Published by AIP Publishing.