Large anomalous Nernst effect in canted antiferromagnet YbMnBi₂

Abstract

A large anomalous Nernst effect (ANE) is crucial for thermoelectric energy conversion applications because the associated unique transverse geometry facilitates module 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. $$YbMnBi_2$$, as a canted antiferromagnet, surprisingly shows a large ANE conductivity of $$~10 A m{^−1}$$ \ $$K{^−1}$$ that surpasses large values observed in other ferromagnets (3–5 A m−1 K−1). 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. The high anomalous transverse thermoelectric performance and extremely small magnetization make $$YbMnBi_2$$ an excellent candidate for transverse thermoelectrics.