Harris, A. BrooksLubensky, Tom CMele, Eugene J2023-05-232023-05-231989-08-012015-07-30https://repository.upenn.edu/handle/20.500.14332/43070Using a gauge-invariant tight-binding model on a rigid square lattice, we discuss the transition between a low-temperature flux phase in which orbital magnetic moments alternate antiferromagnetically in sign from plaquette to plaquette and a normal metallic phase. The order parameter, which may be chosen to be the magnetic flux penetrating a plaquette, goes continuously to zero at the transition. We also consider similar phases in a model with m spin colors antiferromagnetically exchange coupled.PhysicsArticle