Using heuristic arguments and numerical simulations it is argued that the critical exponent $\nu$ describing the localization length divergence at the integer quantum-Hall transition is modified in the presence of spin-orbit scattering with short-range correlations. The exponent is very close to $\nu =4/3$, the percolation correlation length exponent, consistent with the prediction of a semiclassical argument. In addition, a band of weakly localized states is conjectured.

• Received 31 July 2001

DOI:https://doi.org/10.1103/PhysRevLett.89.076602