Thermal conductivity reduction by acoustic Mie resonance in nanoparticles

We evaluate the impact of acoustic Mie resonance in nanoparticles on the thermal conductivity of semiconductor and polymer composites. By appropriately choosing the bulk modulus and density, and selecting the size of the nanoparticle to align the Mie resonances with the dominant portion of the thermal conductivity spectrum, we show that large reductions in thermal conductivity are achievable with a dilute concentration of nanoparticles. This can be useful for enhancing ZT for thermoelectric applications, since a dilute loading of particles will minimally impact electrical conductivity. We apply the model to explain the steep reduction in thermal conductivity observed previously in semiconductor alloys and then show that acoustic Mie resonance in polysiloxane nanoparticles can be used to reduce the thermal conductivity of an amorphous polymer by nearly a factor of two.