Low-temperature renormalization-group study of uniformly frustrated models for type-II superconductors

[摘要] We study phase transitions in uniformly frustrated SU(N)-symmetric (2 + epsilon)-dimensional lattice models describing type-II superconductors near the upper critical magnetic field H-c2(T). The low-temperature renormalization-group approach is employed for calculating the beta function beta(T,f) with f an arbitrary rational magnetic frustration. The phase-boundary line H-c2(T) is the ultraviolet-stable fixed point found from the equation beta(T,f)=0, the corresponding critical exponents being identical to those of the nonfrustrated continuum system. The critical properties of the SU(N)-symmetric complex Ginzburg-Landau model are then examined in (4 + epsilon) dimensions. The possibility of a continuous phase transition into the mixed state in such a model is suggested. [S0163-1829(98)00441-X].

[关键词] LARGE-N LIMIT;PHASE-TRANSITIONS;MAGNETIC-FIELD;2 DIMENSIONS;LATTICE;SYSTEMS;GAUGE