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Weyl semimetals (WSM) combine both topological and semimetallic effects, making them candidates for interesting thermoelectric transport properties. Single-crystalline NbP, a Type I WSM, was previously shown to have a large Nernst thermopower, a small Seebeck thermopower, and no magneto-Seebeck effect [1]. However, Skinner and Fu predict this class of materials contains a large, linear-in-field magneto-Seebeck effect [2]. Here, we present results on polycrystalline NbP indicating a large Nernst effect, albeit reduced from that seen in a single crystal, existing simultaneously with an enhanced Seebeck thermopower and a large magneto-Seebeck effect. We propose that slight doping, found present in the polycrystalline sample of NbP, alters the location of the Fermi level enough to allow this to be observed. The presence of both a large Nernst and magneto-Seebeck thermopower is uncommon and could have unique device advantages if used additively. We extend our work to WTe₂, a Type II WSM, through characterization of both longitudinal and transverse thermoelectric and thermomagnetic transport measurements.

[1] S. J. Watzman et al. Phys. Rev. B 97(16), 161404(R) (2018).

[2] B. Skinner and L. Fu. Sci. Adv. 4(5) (2018).