Orbital-selective correlations in kagome flat bands of Co₃Sn₂S₂

Geometrical flat bands provide an ideal platform for studying electronic correlations and quantum-geometric effects. Although the ferromagnetic Weyl semimetal is generally considered a moderately correlated system, recent spectroscopy experiments have revealed a flat-band feature near the Fermi level () that is absent in conventional density functional theory (DFT) calculations. Using DFT plus dynamical mean-field theory and a minimal kagome model, we show that this feature arises not from heavy-fermion-like dynamical band renormalization, but from the shifting of a dx²-y² dominated geometrical kagome flat band toward driven by orbital- and spin-dependent self-energies. The relocated flat band enhances the local Berry curvature near , resulting in a strongly energy-dependent anomalous Hall conductivity and a giant anomalous Nernst effect. Our findings establish an orbital-selective correlation mechanism for positioning geometrical flat bands at , and propose anomalous thermoelectric transport as a sensitive probe of flat band induced topology.