Electric field scaling at a B=0 metal-insulator transition in two   dimensions
  The non-linear (electric field-dependent) resistivity of the 2D electron system in silicon exhibits scaling as a function of electric field and electron density in both the metallic and insulating phases, providing further evidence for a true metal-insulator transition in this 2D system at B=0. Comparison with the temperature scaling yields separate determinations of the correlation length exponent, \nu=1.5, and the dynamical exponent, z=0.8, close to the theoretical value z=1. 
S. V. Kravchenko, D. Simonian, M. P. Sarachik, Whitney Mason, and J.   E. Furneaux