Heat management has emerged as a critical bottleneck in sustaining the miniaturization of electronic devices, primarily due to the inherent challenges in controlling phonons, the dominant heat carriers in semiconductors. In the last decades, advances in nanostructuration have enabled a new degree of control in thermal properties, by tuning how phonons can propagate across the material’s crystal lattice. However, those approaches remain passive and static, therefore they are unsuitable for the very often dynamical heat loads that electronic devices have to cope with.

This project seeks to realize a proof of concept of electrically-actuated thermal transistor, i.e. a device capable of actively tuning its thermal conductance. This design leverages the unique properties of perovskite ferroelectric oxides, which can be electrically polarized to alter the symmetry of their crystal lattice, thereby modulating thermal conductivity. In order to validate this idea, this project proposes the fabrication of silicon microdevice featuring suspended thin films of such materials of interest to experimentally validate the feasibility of dynamically tuning the thermal conductance of the device using an applied electrical field. A clear pathway is defined for the implementation of an AC electrothermal experiment to test the design envisioned. Additionally, alternative approaches are thoughtfully devised as part of a robust risk mitigation strategy.

In order to carry out such goal, Dr. Jose M. Sojo will manufacture the microdevices required for the implementation of the experiments aimed in this proposal, while experiments will be performed in the group’s laboratories. Collaboration with Prof. Andrea Caviglia’s group at the University of Genève will ensure access to high-quality perovskite ferroelectric oxide samples, leveraging their expertise in material deposition. The project will also benefit from theoretical insights provided by Dr. Ricardo Rurali from the Materials Science Institute of Barcelona, strengthening the collaboration network.