Plateau Behavior in the Chiral Luttinger Liquid Exponent

We examine the I-V power law exponent, alpha, for electron tunneling into the fractional quantum Hall edge by filling factors, nu, below 0.4 (or inverse filling, 1/nu > 2.5). In two samples of substantially different densities, the exponent versus 1/nu exhibits a sudden change in slope as it approaches 3 in its value. In sample 1, the slope is reduced from 1.2 to 0.5 while in the sample 2, a much more dramatic reduction, from 1.9 to 0.2, is observed. The latter result is suggestive of a plateau behavior. The filling factor where this reduction in slope occurs is substantially different from theoretical prediction and appears to scale roughly with the enhanced edge electron density rather than the bulk density.