Experimental σxx vs. σxy Scaling Diagram of the Fractional Quantum Hall Effect
Recently, LAUGHLIN et al.  have proposed a σxx vs σxy scaling diagram for the hierarchical sequence of fractional quantum Hall effect (FQHE) ground states at filling factors r=p/q. The diagram contains ‘delocalization’ fixed points (denoted DF below) which determine the branching of flow trajectories to successively higher—order daughter states of the hierarchy and ‘mobility’ fixed (MF) points which account for the destruction of fractional states by disorder. Although flow lines in this theory correspond to T=0 length scale transformations, the effective sample size is related to an inelastic scattering length and the diagram can be probed experimentally by varying T. It is predicted  that DF points should scale as (e*)2/Г where e* is the quasiparticle charge and Г is a disorder parameter. Our objective is to establish the fixed points and flow topology experimentally to test the validity of scaling theory in the FQHE regime and the relation e*=±e/q.
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