Thomson cooling during thermally induced phase transition

Nontechnical Description

Effective cooling and heat dissipation are essential for managing heat in microelectronics. This is particularly important as microelectronics continue to shrink and pack more processing power into smaller spaces. Just consider how hot a mobile phone can get in normal use.

Thomson cooling is a solid-state cooling method that was proposed by Lord Kelvin in 1850, but it has not been commercialized due to the limited cooling power observed in most materials. Recent measurements have revealed promising materials with a strong thermal response due to thermally induced magnetic and structural phase changes. These findings suggest the potential to design highly efficient Thomson coolers.

This project establishes a new paradigm for Thomson materials and provides fundamental insights that will guide the future design of Thomson materials for electronic cooling. Additionally, investigators aim to co-design hybrid modules that can be used at low temperatures as an alternative to helium-based refrigeration. This addresses the current helium shortage and reduces related costs.

Educational initiatives involve engaging graduate and undergraduate students, as well as organizing hands-on workshops and classes for elementary and middle school students. These initiatives aim to introduce students to the principles of thermodynamics and materials science. Technical Description

Investigators will study the Thomson effect systematically in thermally induced phase transitions across two distinct classes of materials: 1) a subset of Heusler compounds with promising characteristics as both magnetocaloric and thermoelectric materials during their first-order magneto-structural phase transitions. 2) Transition metal dichalcogenides, investigated during structural (e.g., from 2H to 1T) phase transitions and electronic phase transitions (e.g., charge density wave transitions). At the phase transition point, numerous transport properties undergo simultaneous changes, enabling the development of multifunctional materials.

The investigators focus on gaining fundamental understanding of electronic and phononic characteristics, and their relationship to the structural changes in the materials, using a combined theoretical and experimental approach with an iterative feedback loop. Through these studies, the PIs aim to identify material metrics relevant to the design and coefficient of performance of Thomson coolers under both continuous and transient operation, as well as hybrid structures integrating Thomson coolers with magnetocaloric or Ettingshausen coolers.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.