Metal-insulator transitions in the disordered Hubbard model

Karim Bouadim, Nganba Meetei, Yen Lee Loh +1 more

Joseph C. Szabo, Kyungmin Lee, Nandini Trivedi +1 more

R. Bulla, Thomas Pruschke, Alex C. Hewson

Lingyu Tian, Yueqi Li, Ying Liang +1 more

We study the effect of disorder and doping on the metal-insulator transition in a repulsive Hubbard model on a square lattice using the determinant quantum Monte Carlo method. First, with the aim of making our results reliable, we compute the sign problem with various parameters such as temperature, disorder, on-site interactions, and lattice size. We show that in the presence of randomness in the hopping elements, the metal-insulator transition occurs and the critical disorder strength differs at different fillings. We also demonstrate that doping is a driving force behind the metal-insulator transition.

Yueqi Li, Lingyu Tian, Tianxing Ma +1 more

Using the determinant quantum Monte Carlo method, we investigate the metal-insulator transition in the interacting disordered Hubbard model of a Lieb lattice in which the system characterizes the flat band centered at the Fermi level. By choosing suitable electron densities, we ensure the weak interaction sign problem to improve the reliability of our results. It is found that disorder and on-site Coulomb repulsive interaction produce interesting effects that induce the metal-insulator transition which is impossible in the half-filled case. The density of states at the Fermi energy is still finite in the thermodynamic limit, suggesting that the system is an Anderson insulator rather than a Mott insulator. Moreover, this doping system is paramagnetic, unlike the half-filled system which is ferrimagnetic.

M. G. Zacher, Ansgar Dorneich, C. Gröber +2 more