Possibility of a new type of mixed state in high-temperature superconductors

Both the temperature {ital T} and magnetic field {ital H} above some critical value destroy the superconducting state. The mixed state of a type-II superconductor makes it possible to sustain superconductivity in fields exceeding the thermodynamic critical field {ital H}{sub {ital c}}. We hypothesize the possibility of a new type of mixed state, present even in the absence of a magnetic field, which would allow superconductivity to exist at temperatures much higher than the critical temperature {ital T}{sub {ital c}} allowed by the conventional BCS theory.