Composite edge states in the ν=2/3 fractional quantum Hall regime

A generalized ν=2/3 state, which unifies the sharp edge picture of MacDonald with the soft edge picture of Chang and of Beenakker is presented and studied in detail. Using an exact relation between correlation functions of this state and those of the Laughlin ν=1/3 wave function, the correlation functions of the ν=2/3 state are determined via a classical Monte Carlo calculation, for systems up to fifty electrons. It is found that as a function of the slope of the confining potential there is a sharp transition of the ground state from one description to the other. The experimental implications are discussed.