Defect-limited thermal conductivity in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>MoS</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:math>
Carlos A. Polanco, Tribhuwan Pandey, Tom Berlijn, Lucas Lindsay
Abstract
The wide measured range of thermal conductivities $(k)$ 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 $({V}_{\mathrm{S}})$, 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.