Spin-0 Mott insulator to metal to spin-1 Mott insulator transition in the single-orbital Hubbard model on the decorated honeycomb lattice

We study the interplay of strong electron correlations and intratriangle spin exchange at two-thirds filling single-orbital Hubbard model on decorated honeycomb lattice using rotationally invariant slave bosons. find that tunes between a spin-1 Mott insulator, metal, spin-0 insulator when is antiferromagnetic. The insulators occur from effective multiorbital interactions are adiabatically connected to ground state an isolated triangle. An antiferromagnetic exchange, as determined by Goodenough-Kanamori rules, may in coordination polymers kinetic via ligands. characterize magnetism regime where triplets dominate. For small $U$ Slater occurs with order triangles. Magnetism described Heisenberg lattice, whose N\'eel ordered.