Model for thermal conductivity in nanoporous silicon from atomistic simulations

By means of molecular dynamics simulations, we have studied heat transport in nanoporous silicon, finding that the Eucken model, widely adopted in the description of thermal transport in macroporous systems, breaks down when pores are nanometer-sized. Present atomistic results are used to inform an extension to this model, effectively describing the relationship between thermal conductivity and interface density, here identified as the key structural characteristic of a porous sample. Our model, validated against a range of pore sizes and distributions, provides a robust framework for the interpretation of the atomistic results, as well as suggesting how to estimate the average pore size through thermal transport measurements.