Ff. Assaad et M. Imada, INSULATOR-METAL TRANSITION IN THE ONE-DIMENSIONAL AND 2-DIMENSIONAL HUBBARD MODELS, Physical review letters, 76(17), 1996, pp. 3176-3179
We use quantum Monte Carlo methods to determine T = 0 Green functions,
G((r) over right arrow,omega), on lattices up to 16 x 16 for the 2D H
ubbard model at U/t = 4. For chemical potentials mu within the Hubbard
gap \mu\ < mu(c) and at long distances (r) over right arrow, G((r) ov
er right arrow, omega = mu) similar to e(-\(r) over right arrow\/xi l)
with critical behavior xi(l) similar to \mu - mu(c)\(-nu), nu = 0.26
+/- 0.05. This result stands in agreement with the assumption of hyper
scaling with correlation exponent nu = 1/4 and dynamical exponent z =
4. In contrast, the generic band insulator as well as the metal-insula
tor transition in the 1D Hubbard model are characterized by nu = 1/2 a
nd z = 2.