Parabolic mirrors collimating and focusing fluxes of thermal phonons

Manipulating heat fluxes at the nanoscale has become increasingly important in modern microelectronics. However, many methods of heat manipulations rely on complex nanofabrication. Here, we propose simple designs for collimation and focusing of thermal phonons based on parabolic mirrors that require no nanofabrication. We perform Monte Carlo simulations of a ballistic phonon transport in silicon membranes with parabolic boundaries. Our simulations demonstrate that parabolic surfaces can act as parabolic mirrors for phonons, thus collimating or focusing phonon fluxes in semiconductors. Such parabolic mirrors can create a directional flux of thermal phonons emitted from a nanoscale hot spot or focus a collimated phonon flux into a hot spot. These devices open new possibilities in the thermal management of low-temperature systems, such as quantum circuits or cryogenic particle detectors.

Automated summary

Manipulating heat flux at the nanoscale is crucial in modern microelectronics, but it often requires complex nanofabrication techniques. This study proposes simple designs using parabolic mirrors for collimation and focusing of thermal phonons without the need for nanofabrication. Monte Carlo simulations demonstrate that parabolic surfaces can act as mirrors to collimate or focus phonon fluxes in semiconductors. These devices have the potential to revolutionize the thermal management of low-temperature systems, such as quantum circuits or cryogenic particle detectors.