Method for Enhancing the Anomalous Nernst Effect in Magnetic Weyl Semimetals

The Nernst effect is the generation of transverse current in a material exposed to a perpendicular temperature gradient and magnetic field. In magnetic materials, an anomalous Nernst effect (ANE) can occur even in the absence of an external field. Using such a transverse configuration to convert heat to electricity might allow for more efficient thermoelectrics than the standard longitudinal geometry, but in conventional materials the ANE is too small to create practical devices. Recently, magnetic Weyl semimetals (MWSM) have emerged as a platform to generate a large ANE. MWSMs host topologically protected pairs of Weyl points which generate large Berry curvatures and can potentially lead to large ANE. Here we introduce a method for further enhancing the ANE by tuning the positions of Weyl point pairs using an external magnetic field, to induce constructive superposition of their ANE signals. We illustrate this procedure using a multi-band model and present density functional theory calculations that motivate the experimental realization of these effects in Heusler materials.<br/><br/>V.I. was supported by the U.S. Department of Energy Office of Science, Office of Fusion Energy Sciences, under Contract No. DE-AC02-05CH11231. E.B. acknowledges support from the National Science Foundation Graduate Research Fellowship under Grant No. 1752814. L.Z.T. was supported by the Molecular Foundry, a DOE Office of Science User Facility supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. This research used resources of the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.