A new broken U(1)-symmetry in extreme type-II superconductors
Norwegian University of Science and Technology - N-7034 Trondheim,
2 California Institute of Technology - Pasadena CA91125, USA
Accepted: 15 April 1999
A phase transition within the molten phase of the Abrikosov vortex system without disorder in extreme type-II superconductors is found via large-scale Monte-Carlo simulations. It involves breaking a U(1)-symmetry, and has a zero-field counterpart, unlike vortex lattice melting. Its hallmark is the loss of number-conservation of connected vortex paths threading the entire system in any direction, driving the vortex line tension to zero. This tension plays the role of a generalized "stiffness” of the vortex liquid, and serves as a probe of the loss of order at the transition, where a weak specific heat anomaly is found.
PACS: 74.20.De – Phenomenological theories (two-fluid, Ginzburg Landau, etc.) / 74.25.Dw – Superconductivity phase diagrams / 74.25.Ha – Magnetic properties
© EDP Sciences, 1999