Gilad Barak, Georg Schusteritsch, Amir Yacoby, Bertrand Halperin, Loren N. Pfeiffer, Ken W. West

Quantum Hall edges are predicted to reconstruct as a result of the competition between quantum confinement and Coulomb interaction. In this work we study such edge reconstruction in a quantum wires subject to a quantizing magnetic field. Using momentum resolved tunneling, we map the electronic dispersions in the wire as a function of external magnetic field. At a critical magnetic field a spin polarized strip of electrons develops along the soft confining edge of the wire. We associate this behavior with the Dempsey Gelfand Halperin edge reconstruction predicted in 93'. This edge reconstruction is characterized by a second order phase transition driven by the strength of the confining potential and whose order parameter is the width of the polarized strip and. We find quantitative agreement between the measured width of the polarized strip and theory.