Magnon-induced Giant Anomalous Nernst Effect in Single Crystal MnBi

Abstract

Thermoelectric modules are a promising approach to energy harvesting and efficient cooling. In addition to the longitudinal Seebeck effect, recently transverse devices utilizing the anomalous Nernst effect (ANE) have attracted interest. For high conversion efficiency, it is required that the material should have a large ANE thermoelectric power and low electrical resistance, the product of which is the ANE conductivity. ANE is usually explained in terms of intrinsic contributions from Berry curvature. Our observations suggest that extrinsic contributions also matter. Studying single-crystal MnBi, we find a very high ANE thermopower (~10 $\mu$V/K) under 0.6 T at 80 K, and a transverse thermoelectric conductivity of over 40 A/Km. With insight from theoretical calculations, we attribute this large ANE predominantly to a new advective magnon contribution arising from magnon-electron spin-angular momentum transfer. We propose that introducing large spin-orbit coupling into ferromagnetic materials may enhance the ANE through the extrinsic contribution of magnons.

14 pages, 4 figures

References in corpus (5)

• Spin Seebeck insulator
• Observation of the Spin-Seebeck Effect in a Ferromagnetic Semiconductor
• Berry phase effect in anomalous thermoelectric transport
• Symmetry-lowering lattice distortion at the spin-reorientation in MnBi single crystals
• Enhanced anomalous Nernst effect in disordered Dirac and Weyl materials

Cited by in corpus (14)

• Observation of the anomalous Nernst effect in altermagnetic candidate Mn5Si3
• Creation of flexible spin-caloritronic material with giant transverse thermoelectric conversion by nanostructure engineering
• Fundamentals and advances in transverse thermoelectrics
• First-principles calculation of anomalous Hall and Nernst conductivity by local Berry phase
• High power density energy harvesting devices based on the anomalous Nernst effect of Co/Pt magnetic multilayers
• Multifunctional composite magnet realizing record-high transverse thermoelectric generation
• Modulation of the Nernst Thermoelectrics by Regulating the Anomalous Hall and Nernst Angles
• Ultrahigh Anomalous Nernst Thermopower and Thermal Hall Angle in YbMnBi2
• Large asymmetric anomalous Nernst effect in the antiferromagnet SrIr${}_{0.8}$Sn${}_{0.2}$O${}_3$
• Giant anomalous Nernst signal in the antiferromagnet YbMnBi2
• High-throughput development of flexible amorphous materials showing large anomalous Nernst effect via automatic annealing and thermoelectric imaging
• Colossal Layer Nernst Effect in Twisted Moiré Layers
• Designing flexible hard magnetic materials for zero-magnetic-field operation of the anomalous Nernst effect
• Topological transverse spin transport in a canted antiferromagnet/heavy metal heterostructure