Field-induced Kosterlitz-Thouless transition in the n=0 Landau level of graphene

Phys Rev Lett. 2009 Nov 20;103(21):216801. doi: 10.1103/PhysRevLett.103.216801. Epub 2009 Nov 20.


At the charge neutral point, graphene exhibits a very unusual high-resistance metallic state and a transition to a complete insulating phase in a strong magnetic field. We propose that the current carriers in this state are the charged vortices of the XY valley-pseudospin order parameter, a situation which is dual to a conventional thin superconducting film. We study energetics and the stability of this phase in the presence of disorder.