Reconstruction near the interface of a ν=4 and ν=3 QH systems*

We study the Hartree-Fock ground state near the interface between the ν=4 and ν=3 quantum Hall systems. In this problem we have two tuning parameters, w which is the width of interface in units of l (magnetic length), and Ec which is the strength of coulomb interaction in units of the cyclotron energy. In the bulk, for 2.52 < Ec <2.94, the ν=3 state is fully polarised but ν=4 state is a singlet. We have found that in this regime there are two edge phases. Phase 1 has 3 chiral modes, 2 downstream and 1 upstream. In this phase spin is a good quantum number. In Phase 2 we only found 1 chiral mode which is downstream. This phase has a spin rotation and can have a pair of counter propagating neutral modes. We use the time dependent Hartree-Fock method to calculate the collective excitations of these phases.