Vortex-glass phases in type-II superconductors

Abstract

A review is given on the theory of vortex-glass phases in impure type-II\nsuperconductors in an external field. We begin with a brief discussion of the\neffects of thermal fluctuations on the spontaneously broken U(1) and\ntranslation symmetries, on the global phase diagram and on the critical\nbehaviour. Introducing disorder we restrict ourselves to the experimentally\nmost relevant case of weak uncorrelated randomness which is known to destroy\nthe long-ranged translational order of the Abrikosov lattice in three\ndimensions. Elucidating possible residual glassy ordered phases, we distinguish\nbetwee positional and phase-coherent vortex glasses. The discussion of elastic\nvortex glasses, in two and three dimensions occupy the main part of our review.\nIn particular, in three dimensions there exists an elastic vortex-glass phase\nwhich still shows quasi-long-range translational order: the `Bragg glass'. It\nis shown that this phase is stable with respect to the formation of\ndislocations for intermediate fields. Preliminary results suggest that the\nBragg-glass phase may not show phase-coherent vortex-glass order. The latter is\nexpected to occur in systems with weak disorder only in higher dimensions. We\nfurther demonstrate that the linear resistivity vanishes in the vortex-glass\nphase. The vortex-glass transition is studied in detail for a superconducting\nfilm in a parallel field. Finally, we review some recent developments\nconcerning driven vortex-line lattices moving in a random environment.\n