Lattice thermal conductivity of nanoporous Si: Molecular dynamics study

Lattice thermal conductivity κl of Si with nanometer-sized pores along the 001 direction is calculated as a function of pore diameter (dp) and pore spacing (ds) by employing a molecular dynamics approach. Our results show that κl across pores is smaller than the bulk value by over two orders of magnitude at room temperature, and that it decreases (increases) as a function of dp (ds) for fixed ds (dp). This behavior is shown to originate from the reduction in the channels for phonon transport and the increased phonon scattering at the pore surfaces.