Quantum Hall states can be characterized by their chiral edge modes. Upon softening the edge potential, the edge has long been known to undergo spontaneous reconstruction driven by charging effects. I will discuss [1] a new type of quantum phase transitions at the edge, which are qualitatively distinct from charge-driven transitions. The spin-switching phase transition is driven by exchange effects, and is manifest by an abrupt change in the ordering of the chiral modes at the edge. I will specifically discuss the nu = 3 scenario. The transition occurs as the edge potential is made softer, while the ordering in the bulk remains intact. This phenomenon is robust, and has many veriable experimental signatures in transport.

1. U. Khanna, G. Murthy, S. Rao, Y. Gefen, submitted.