Recycling Waste Heat in Phononics Technology Via Thermal Hall Effect

Abstract

More than 60% of the energy produced in the US, including renewable sources such as solar cells, is wasted as heat. Therefore, recycling the waste heat into a useable form is becoming an area of critical global interest. In recent years, phononics—a field focused on controlling the heat for applications—has emerged as a new technology. Phonons are the quanta of thermal energy that propagate under a temperature difference. There are several theoretical proposals for phononic devices such as thermal diodes, transistors, and logic gates. However, a fundamental challenge is controlling the flow of heat in such devices using a property known as the thermal Hall effect, which is negligible in most materials, because phonons are chargeless and do not respond to external electromagnetic fields. The goal of this SIGECS proposal is to identify and characterize materials with large thermal Hall effect for next-generation phononic applications. The project will deliver a unique instrumentation for high throughput characterization of candidate materials and will generate thermal Hall data for a steady stream of publications and presentations. It will facilitate joint grant applications between physics and engineering departments, and will become an advanced technological platform for training the future workforce.