2D material thermal metrology and usage for Solid-State Cooling

Micron-scale on-chip cooling, heat management, and precise temperature control are increasingly critical as electronic technologies advance toward nanoscale transistors, compact systems, wearables, and portable thermal devices. Conventional mechanical refrigerators with moving parts are unsuitable at these length scales due to fundamental limits on miniaturization. As a result, solid-state cooling approaches that rely on passive and active heat transfer, without moving components, are required. Among these approaches, two-dimensional (2D) materials and thin films are particularly attractive due to their compatibility with chip-scale integration.

A key first step toward implementing such technologies is accurate thermal characterization, especially in-plane thermal conductivity measurements of supported 2D materials and thin films. In this talk, I will review our work on thermal conductivity measurements in supported 2D systems and thin films, as well as the design of micro- and nanoscale solid-state coolers that offer alternatives to conventional thermoelectric devices. These approaches focus on controlling heat flow using electric and magnetic fields. We have recently demonstrated enhanced nanoscale Peltier cooling through geometric constriction. In this nozzle-like structure, electron expansion under an applied bias generates additional cooling that is additive to conventional Peltier effects. I will also discuss Thomson cooling and materials design strategies that enable large Thomson coefficients near structural, electronic, or magnetic phase transitions. Finally, I will present our recent studies of metallic alloys for active solid-state cooling applications.

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