Giant Specific Power Generation Capacity of Micro‐Thermoelectric Generators Enabled by High‐Entropy Cocktail Strategy

Abstract

ABSTRACT Specific power generation capacity Γ P is a critical performance metric for micro‐thermoelectric generators ( μ ‐TEGs), yet the best reported values are constrained to a few hundred µW cm −2 K −2 . Here, we report a giant Γ P of ∼5000 µW cm −2 K −2 in μ ‐TEGs based on the anomalous Nernst effect (ANE) in medium‐entropy (FeCoNi) 100‐ x Pt x films. Leveraging the high‐entropy cocktail strategy, we have simultaneously achieved a large anomalous Nernst thermopower S xy (>1.4 µV K −1 ) and low resistivity ρ xx (<85 µΩ cm), and suppressed the classical and quantum size effects on both S xy and ρ xx at the optimal composition of x ≈ 50 and film thickness of a few nanometers, enabling the record‐high Γ P . The underlying mechanism arises from cocktail‐driven modulation of energy‐band smearing, density of states, and Berry curvature at the Fermi surface, resulting in an ultrashort carrier mean‐free‐path of ∼3 nm, an ultrahigh carrier density of ∼10 23 cm −3 , and a large anomalous Nernst conductivity above 1.7 A m −1 K −1 . This claim is further supported by first‐principles calculations, which collectively highlight the experimental and theoretical potential of utilizing such materials for high‐performance μ ‐TEG applications.