Novel Thermal Transport Phenomena in Quantum Materials

Regents Of The University Of Michigan - Ann Arbor, Ann Arbor MI

Investigators

Abstract

Non-technical Abstract: Electrons carry not only electricity but also energy. This property of electrons is a powerful probe for quantum materials. Moving the electrons with heat generates electrical voltages or reveals thermal conductions in the solids. These mobile electrons may change the moving directions under a magnetic field, leading to transverse electrical voltages and thermal conductions. These novel thermal transport properties are essential to detect and probe the ground state of strongly correlated quantum materials. The research brings the potential to open the door to studying the interplay between strong-correlation effects and topology in the search for new quantum phases, novel topological phases, and new multi-functionalities for future electronics. The project also provides opportunities to train undergraduate and graduate students in the science and technology of this quantum world. By involving undergraduates in research, creating opportunities to promote the integration of women and minorities in careers in science and engineering, bringing local school students to laboratories, and communicating research to the broader public, the team brings the general public the advancements in strongly correlated materials and develops excitement, awareness, and interest in the field of quantum science and condensed matter physics. Technical Abstract: The research project aims to investigate strongly correlated materials using novel thermal transport properties. Bridging the research fields of strongly correlated materials and topological quantum materials, the research team will use the thermoelectric effect and thermal Hall effect to reveal the physical origin of recently observed novel phenomena of strongly correlated materials: (1) quantum oscillations in Kondo insulators; (2) large thermal Hall effects in undoped and doped Mott insulators; (3) exotic thermal transport in quantum spin liquid; and (4) flat-bland phenomena of Kagome metals. These directions are exciting new developments in long-standing puzzles in condensed matter physics. They share the same debate about the role of the charge-neutral quasiparticles in the strongly interacted states: what carries these interesting phenomena: magnon, phonon, Bogoliubov quasiparticles, or even Majorana excitations. The research tasks will answer these questions: (1) What is the nature of the magnetic-field-driven insulator-metal-transition in Kondo insulators? (2) What causes strong Hall signals of the heat current in Mott insulating undoped cuprates? (3) Are the fundamental excitations fermionic or bosonic in Kagome quantum spin liquid? (4) What are the experimental signatures of the flat band in Kagome metals? Answers to these questions will eventually provide the big picture of the electronic and magnetic ground states of strongly correlated 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.