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MA: Fachverband Magnetismus
MA 26: Focus Session: Unconventional Thermoelectric Phenomena and Materials (joint session MA/TT)
MA 26.4: Invited Talk
Wednesday, March 20, 2024, 16:45–17:15, H 1058
Large anomalous Nernst thermoelectric performance in YbMnBi2 — •Yu Pan1,2, Congcong Le2, Bin He2, Sarah Watzman3,4, Mengyu Yao2, Johannes Gooth2, Joseph Heremans3, Yan Sun2, and Claudia Felser2 — 1Chongqing University, Chongqing, China — 2Max Planck Insitute for Chemical Physics of Solids, Dresden, Germany — 3The Ohio University, Columbus, USA — 4University of Cincinnati, Cincinnati, USA
The anomalous Nernst effect (ANE) have attracted increasing attention since the surge of topological semimetals, because the associated unique transverse geometry of ANE facilitates thermoelectric device fabrication. Topological ferromagnets with large Berry curvatures show large ANEs; however, they face drawbacks such as strong magnetic disturbances and low mobility due to high magnetization. Searching for materials with large ANE thermopower, low resistivity (high mobility), and low thermal conductivity are of great interest. It is found that YbMnBi2, as a canted antiferromagnet, present a large ANE competitive to those of ferromagnets while with much lower resistivity and thermal conductivity. The canted spin structure of Mn guarantees a non-zero Berry curvature, but generates only a weak magnetization three orders of magnitude lower than that of general ferromagnets. The heavy Bi with a large spin-orbit coupling enables a large ANE and low thermal conductivity, whereas its highly dispersive px/y orbitals ensure low resistivity. These results suggest YbMnBi2 as an excellent candidate for transverse thermoelectrics.
Keywords: thermoelectric; Berry curvature; antiferromagnet; anomalous Nernst effect; spin-orbit coupling