Impurity-induced Mott transitions in partially filled antiferromagnetic states

In view of cuprate superconductors, effects of point-type repulsive impurity potential (V) on partially filled antiferromagnetic (AF) states are studied for a strongly correlated square-lattice Hubbard model (U/t = 12) with a diagonal transfer (t' = −0.3t), using a variational Monte Carlo method. To simplify interpretation, here we focus on the case of δ imp = δ, where δ imp and δ are densities of impurity sites and doped holes, respectively, with δ = 0.04 − 0.20. As a result, a filling-control-type Mott transition occurs at V = V M (~ 2t) irrespective of δ; a partially filled AF state becomes Mott insulating for V > V M. Such impurity-induced Mott transitions extensively appear beyond the above parameter settings.