It is argued that in two dimensions the high-field zero-temperature phase of a type-II superconductor can be quantum vortex fluid. The average intervortex spacing in this phase takes discrete values, leading to macroscopic steps in the total flux through the superconductor on the applied magnetic field. In the absence of dissipation, the Hall conductivity is quantized in units of 4${\mathit{e}}^2$/πħ.

• Received 7 November 1994

DOI:https://doi.org/10.1103/PhysRevB.51.15351