Critical exponent for the quantum Hall transition

We report an estimate $\nu =2.593$ [2.587,2.598] of the critical exponent of the Chalker-Coddington model of the integer quantum Hall effect that is significantly larger than previous numerical estimates and in disagreement with experiment. This suggests that models of noninteracting electrons cannot explain the critical phenomena of the integer quantum Hall effect.

Figure 1

Simulation data and FSS fit for the Chalker-Coddington model. The different lines correspond to different numbers of nodes $N=16,24,32,48,64,96,128$.

Figure 2

The same as Fig. 2 but with the focus on data near the critical point so as to make the existence of corrections to scaling due to an irrelevant scaling variable evident.