Influence of atomic-scale defect on thermal conductivity of single-layer MoS2 sheet

Recently, single-layer MoS2 has increasingly promised a great potential in both thermoelectric and thermal management application due to its high Seebeck coefficient and intrinsic band gap. Herein, we investigate thermal conductivity of single-layer MoS2 sheet and the effect of atomic-scale lattice defects and temperature on thermal conductivity using non-equilibrium molecular dynamics simulations (NEMD). Simulations results indicate the thermal conductivity can be suppressed by lattice defects and the increase in the range of temperature from 100 K to 400 K. Moreover, the physical mechanism of the thermal conductivity reduction was analyzed based on the phonon group velocity, participation ratio and phonon spectral transmission coefficient. Interestingly, it is revealed that the reduction of thermal conductivity results from the decreased phonon group velocity induced by defects, and phonon localization around lattice defects. Furthermore, the contributions from various frequency range of phonons to the thermal conductivity of pristine and defective structure were quantified. Especially, it is found that the coupling strength of between low-frequency and high-frequency phonons gradually increases due to the introduction of atomic-scale defects. This study is beneficial for thermal management of nanodevices and optimizing the thermoelectric properties of MoS2 based materials.