Kinetic magnetism in the crossover between the square and triangular lattice Fermi-Hubbard models

The ground state of the hard-core Fermi-Hubbard model with a single hole (and otherwise half-filled) is a ferromagnet on the square lattice, but an antiferromagnet on the triangular lattice, as those spin patterns minimize the kinetic energy of the hole. What is the magnetic behavior as one interpolates between these two geometries? Using a sophisticated quantum Monte Carlo algorithm, the authors determine here the magnetic correlations as the lattice is varied. Their calculations are performed in the thermodynamic limit and at temperatures comparable to current cold-atom experiments. They find a magnetic crossover between the two geometries, and calculate signatures of it that are observable in these experiments.