Finite size corrections to scaling laws in the centers of Landau levels are studied systematically by numerical calculations. The corrections can account for the apparent non-universality of the localization length exponent $\nu{ }$. In the second lowest Landau level the irrelevant scaling index is $y_{ \mathrm{ irr}}=-0.38\pm0.04$. 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 length exponent $\nu$ is universal with respect to Landau level index and an additional periodic potential.
Categories: cond-mat