New Phases of High Temperature Superconductors in High Magnetic Field

Abstract

Fluctuation behavior of high temperature superconductors in high magnetic field is studied within the Ginzburg-Landau theory. Landau level degeneracy of Cooper pairs enhances fluctuations which destroy the familiar Abrikosov vortex lattice for D=2,3. Instead, a charge-density wave of Cooper pairs (SCDW) is the new low-temperature phase of the theory. SCDW has no condensate, but differs from the normal state by a periodic modulation of the Cooper pair density. In presence of disorder, the Abrikosov state is revived and both superconducting and density-wave phases are possible.