Single orbital + multiple sites = Rich physics

Since the discovery of the iron-based superconductors, it has become clear that the combination of multiple orbitals and strong correlations can lead to rich physics, beyond what one sees in single orbital routes.
An alternative route to rich physics is a single orbital model on a lattice with multiple sites in a unit cell.

Henry Nourse, Ben Powell, and I just posted a preprint
Multiple insulating phases due to the interplay of strong correlations and lattice geometry in a single-orbital Hubbard model

We find ten distinct ground states for the single-orbital Hubbard model on the decorated honeycomb lattice, which interpolates between the honeycomb and kagome lattices and is the simplest two-dimensional net. The rich phase diagram includes a real-space Mott insulator, dimer, and trimer Mott insulators, a spin-triplet Mott insulator, flat band ferromagnets, and Dirac metals. It is determined as a function of interaction strength, band filling, and hopping anisotropy, using rotationally invariant slave boson mean-field theory.

We welcome comments.