CAREER: Investigation of Anisotropic Restrictions on Charge Carrier Motion in Topological Materials via Magneto-Thermoelectric Transport

Non-technical abstract:

Topological materials are a unique set of materials that conduct electrons differently on their surfaces than they do throughout their bulk. This leads to interesting and unique transport properties and potential to unlocking a new generation of efficient solid-state energy conversion devices. Results of this project will help gain fundamental understanding of the properties of topological materials, allowing their synthesis with most useful properties and usable forms while preserving their unique attributes.

This approach is likely to ultimately enable a new class of efficient energy conversion devices based on strategically designed topological materials. This project also humanizes the fundamental concepts of charge carrier transport through extensive set of outreach and education activities. The research team uses a physical embodiment of charge carrier motion to explain it to a broad general audience and uses creative ways of conveying these concepts and inspiring interest in science.

Technical abstract:

While transport properties of topological materials have strong potential for use in efficient solid-state devices, little progress has been made moving towards their use due to challenges in designing and synthesizing topological material in useful forms. Crucial to this progress is understanding the critical length scales over which topological transport dominates, eliminating stray magnetic fields and reducing externally applied magnetic fields, and understanding transport across magnetic phase transitions.

This project addresses these gaps using magneto-thermoelectric transport as a probe to gain deep insight into the motion of charge carriers. Magneto-thermoelectric transport measurements uniquely interrogate the interplay between heat, charge, and spin with the electronic structure of the material. The principal investigator uses magneto-thermoelectric transport to tease apart the intertwined transport signatures due to the topological band structure itself from the transport signatures stemming from physical length scales of samples, parabolic bands, and magnetic textures.

Results of this work determine the fundamental mechanisms underlying and controlling charge carrier transport in topological materials, informing targeted materials design for enhanced device applications using topological materials.

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.