Novel Collective Excitation in Spin Textured Edges of Quantum Hall Systems

We study the electric and magnetic properties of the edge of a two-dimensional electron gas in presence of a magnetic field and at filling factor unity. The existence of a spin textured edge is proved as a function of the Zeeman coupling and of the smoothness of the confining potential. We also calculate the low energy excitation of the spin textured phase. We obtain that in addition to the classical edge magnetoplasmons at small wavectors, there is an almost dispersionless excitation, with a finite gap of energy at zero wavevector. This excitation is associated with the broken symmetry of the spin textured edge phase.