The Structure of Fractional Edge States: A Composite Fermion Approach

I study the structure of the two-dimensional electron gas edge in the quantum Hall regime using the composite fermion approach. The electron density distribution and the composite fermion energy spectrum are obtained numerically in Hartree approximation for bulk filling factors $\nu=1,1/3,2/3,1/5$. For a very sharp edge of the $\nu=1$ state the one-electron picture is valid. As the edge width $a$ is increased the density distribution shows features related to the fractional states and new fractional channels appear in pairs. For a very smooth edge I find quasiclassically the number of channels $p\sim\sqrt{a/l_H}$, where $l_H$ is the magnetic length.