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

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.