title: Vortex sublattice melting in a two-component superconductor.
abstract: We consider the vortices in a superconductor with two individually conserved condensates in a finite magnetic field. The ground state is a lattice of cocentered vortices in both order parameters. We find two phase transitions: (i) a "vortex sublattice melting" transition where vortices in the field with lowest phase stiffness ("light vortices") lose cocentricity with the vortices with large phase stiffness ("heavy vortices"), entering a liquid state (the structure factor of the light vortices vanishes continuously; this transition is in the 3Dxy universality class); (ii) a first-order melting transition of the lattice of heavy vortices, in a liquid of light vortices.
authors.affiliation: Department of Physics, Norwegian University of Science and Technology, N-7491 Trondheim, Norway.
authors.forename: E
authors.initials: E
authors.lastname: Smørgrav
authors.forename: J
authors.initials: J
authors.lastname: Smiseth
authors.forename: E
authors.initials: E
authors.lastname: Babaev
authors.forename: A
authors.initials: A
authors.lastname: Sudbø