CORRECTIONS TO SCALING IN THE INTEGER QUANTUM HALL-EFFECT

Finite-size corrections to scaling laws in the centers of Landau level s are studied systematically by numerical calculations. The correction s can account for the apparent nonuniversality of the localization len gth exponent nu. In the second lowest Landau level the irrelevant scal ing index is Yirr = -0.38 +/- 0.04. At the center of the lowest Landau level an additional periodic potential is found to be irrelevant with the same scaling index. These results suggest that the localization l ength exponent nu is universal with respect to the Landau level index and an additional periodic potential.