Ferrimagnetism of ultracold fermions in a multiband Hubbard system
Summary
Strongly correlated materials feature multiple electronic orbitals, which are crucial to accurately understanding their many-body properties. In such multiband models, quantum interference can lead to flat energy bands with large degeneracy that gives rise to itinerant magnetic phases. We report on signatures of a ferrimagnetic state realized in a Lieb lattice with ultracold fermions, characterized by antialigned magnetic moments with antiferromagnetic correlations, and concomitant with a
Content
# Ferrimagnetism of ultracold fermions in a multiband Hubbard system
*Published: 2026 May 7*
Strongly correlated materials feature multiple electronic orbitals, which are
crucial to accurately understanding their many-body properties. In such
multiband models, quantum interference can lead to flat energy bands with large
degeneracy that gives rise to itinerant magnetic phases. We report on signatures
of a ferrimagnetic state realized in a Lieb lattice with ultracold fermions,
characterized by antialigned magnetic moments with antiferromagnetic
correlations, and concomitant with a finite spin polarization. The signatures
remain robust when increasing repulsive interactions from the weakly interacting
to the Heisenberg regime and emerge when continuously tuning the lattice unit
cell from a square to a Lieb geometry. Our flexible approach paves the way
toward exploring exotic phases, such as quantum spin liquids in kagome lattices
and heavy fermion behavior in Kondo models.
DOI: 10.1126/science.adq2411