W. Chen, D. Talreja, D. Eichfeld, P. Mahale, N. Nova, H. Cheng, J. Russell, S. Yu, N. Poilvert, G. Mahan, S. Mohney, V. Crespi, T. Mallouk, J. Badding, B. Foley, V. Gopalan, I. Dabo.
Adding nanoscale inclusions into silicon can be used to tailor its thermal conductivity. At the boundary between the wave-like (Rayleigh) and particle-like (Casimir) regimes for phonon transport, a thermal conductivity minimum is hypothesized. Using silicon metalattices with varying silica nanosphere size, a MRSEC research team was able to experimentally demonstrate this minimum through time-domain thermoreflectance measurements and quantitatively describe it with a Casimir-based ballistic theory for heat transport. This result opens up the potential to engineer thermal diodes from these novel nanoscale materials.