The wide measured range of thermal conductivities $\left(k\right)$ for monolayer ${\mathrm{MoS}}_2$ and the corresponding incongruent calculated values in the literature all suggest that extrinsic defect thermal resistance is significant and varied in synthesized samples of this material. Here we present defect-mediated thermal transport calculations of ${\mathrm{MoS}}_2$ using interatomic forces derived from density functional theory combined with Green's function methods to describe phonon-point-defect interactions and a Peierls-Boltzmann formalism for transport. Conductivity calculations for bulk and monolayer ${\mathrm{MoS}}_2$ using different density functional formalisms are compared. Nonperturbative first-principles methods are used to describe defect-mediated spectral functions, scattering rates, and phonon $k$, particularly from sulfur vacancies $\left(V_{\mathrm{S}}\right)$, and in the context of the plethora of measured and calculated literature values. We find that $k$ of monolayer ${\mathrm{MoS}}_2$ is sensitive to phonon-$V_{\mathrm{S}}$ scattering in the range of experimentally observed densities, and that first-principles $k$ calculations using these densities can explain the range of measured values found in the literature. Furthermore, measured $k$ values for bulk ${\mathrm{MoS}}_2$ are more consistent because $V_{\mathrm{S}}$ defects are not as prevalent.

• Received 28 October 2019

DOI:https://doi.org/10.1103/PhysRevMaterials.4.014004