It is known that a system which exhibits a half-filled lowest flat band and the localized one-particle Wannier states on the flat band satisfying the connectivity conditions, is always ferromagnetic. Without the connectivity conditions on the flat band, the system is non-magnetic. We show that this is not always true. The reason is connected to a peculiar behavior of the band situated just above the flat band.
ASJC Scopus subject areas
- Physics and Astronomy(all)