Aw. Sandvik et al., QUANTUM MONTE-CARLO STUDY OF THE ONE-DIMENSIONAL HUBBARD-MODEL WITH RANDOM HOPPING AND RANDOM POTENTIALS, Physical review. B, Condensed matter, 50(15), 1994, pp. 10474-10484
We have studied the effects of random-hopping matrix elements and rand
om potentials on the properties of the one-dimensional Hubbard model.
Using a quantum Monte Carlo technique, disorder-averaged static spin-
and charge-density susceptibilities have been evaluated for various st
rengths of the disorder. Results for the spin susceptibility at wave n
umber q = 2k(F) indicate that this quantity, which is the fastest dive
rging susceptibility of the pure system, diverges as T --> 0 also when
there is randomness in the hopping matrix elements, but not in the pr
esence of random potentials. Both types of disorder cause a divergence
of the uniform magnetic susceptibility. However, for random potential
s a finite critical strength of the disorder appears to be required. A
t half-filling the transition from Mott (gapped) to Anderson (gapless)
insulating behavior has been studied. A critical disorder strength is
needed to destroy the gap, in agreement with Ma's renormalization gro
up calculations.