Directly probe local moments associated with the lower Hubbard band in CsCr6Sb6

Determine and directly detect the localized magnetic moments associated with the occupied lower Hubbard band that arises from correlation-induced splitting of the kagome flat band in the bilayer kagome metal CsCr6Sb6, and characterize their properties to confirm that these moments are the ones that hybridize with itinerant electrons at low temperature.

Background

The paper argues that strong electron correlations split a kagome-derived flat band in CsCr6Sb6 into upper and lower Hubbard bands, and that the occupied lower Hubbard band provides localized magnetic moments that later hybridize with itinerant electrons, producing Kondo-like signatures.

While STM/STS and ARPES jointly reveal Hubbard-like features at ±50 meV and momentum-dependent hybridization near the Fermi level, the authors note that no direct experimental probe of the proposed local moments associated with the lower Hubbard band has yet been achieved.