A recent study showed that, in spin-1 chiral fermion systems composed of two linearly dispersing bands and one trivial band, impurity scattering produces an asymmetric cusp in the spectral conductivity $\sigma \left(\epsilon \right)$. We demonstrate that this asymmetric cusp markedly enhances the electronic thermoelectric response. Using linear-response theory within the self-consistent Born approximation, we find low-temperature enhancements in both the Seebeck coefficient and the electronic figure of merit. Increasing the curvature of the trivial band further strengthens this cusp-induced enhancement, even though the corresponding density of states becomes smoother. To clarify this mechanism, we introduce a minimal cusp model for $\sigma \left(\epsilon \right)$ and show that the enhancement is most pronounced when the cusp is sharp and strongly asymmetric and when the spectral conductivity at the cusp energy is small.

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• Quantum transport
• Thermoelectrics
• Topological metamaterials
• Weyl semimetal
• Linear response theory