Nernst power factor and figure of merit in the compensated semimetal ScSb

Recently, topological semimetals have emerged as strong candidates for solid-state thermomagnetic refrigerators due to their enhanced Nernst effect. This enhancement arises from the combined contributions of the Berry-curvature-induced anomalous Nernst coefficient associated with topological bands and the normal Nernst effect resulting from synergistic electron-hole compensation. Generally, these two effects are intertwined in topological semimetals, making it challenging to evaluate them independently. Here, we report the observation of a high Nernst effect in the electron-hole compensated semimetal ScSb with topologically trivial electronic band structures. Remarkably, we find a high maximum Nernst power factor of PFN ~ 35 x 10⁻⁴ W m⁻¹ K⁻² in ScSb. The Nernst thermopower (S_xy) exhibits a peak of ~47 µV/K at 12 K and 14 T, yielding a Nernst figure of merit (zN) of ~28 x10⁻⁴ K⁻¹. Notably, despite its trivial electronic band structure, both the PFN and zN values of ScSb are comparable to those observed in topological semimetals with Dirac band dispersions. The origin of the large Nernst signal in ScSb is explained by compensated electron and hole carriers, through Hall resistivity measurements, angle-resolved photoemission spectroscopy, and density functional theory calculations.