Systematic analysis of the Hubbard model on the checkerboard lattice

We study a geometrically frustrated Hubbard model on the checkerboard lattice with the nearest neighbor (t) and diagonal (t') hoppings. By using the path-integral renormalization group method, we calculate the double occupancy and the equal-time spin correlation to discuss the ground-state properties at half filling. It is found that the increase of the Coulomb interaction induces the first-order metal-insulator transition to the antiferromagnetically ordered phase for t'/t=0.2. On the other hand, when t'/t=1.0, magnetic correlations are suppressed, where the non-magnetic Mott insulator phase is stabilized in the strong coupling case