Strain effects on the phonon thermal properties of ultra-scaled Si nanowires

Abstract

The impact of uniaxial and hydrostatic stress on the ballistic thermal conductance (κl) and the specific heat (Cν) of [100] and [110] Si nanowires are explored using a Modified Valence Force Field phonon model. An anisotropic behavior of κl and isotropic nature of Cν under strain are predicted for the two wire orientations. Compressive (tensile) strain decreases (increases) Cν. The Cv trend with strain is controlled by the high energy phonon sub-bands. Dominant contribution of the low/mid (low/high) energy bands in [100] ([110]) wire and their variation under strain governs the behavior of κl.