4 research outputs found
Vortex Lattice Structure of Fulde-Ferrell-Larkin-Ovchinnikov Superconductors
In superconductors with singlet pairing, the inhomogeneous
Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state is expected to be stabilized by a
large Zeeman splitting. We develop an efficient method to evaluate the
Landau-Ginzburg free energies of FFLO-state vortex lattices and use it to
simplify the considerations that determine the optimal vortex configuration at
different points in the phasediagram. We demonstrate that the order parameter
spatial profile is completely determined, up to a uniform translation, by its
Landau level index n and the vortex Lattice structure and derive an explicit
expression for the order parameter spatial profile that can be used to
determine n from experimental data.Comment: 6 pages with one embedded color figure. Minor changes. Final version
as publishe
Fluctuation-Driven First-Order Transition in Pauli-limited d-wave Superconductors
We study the phase transition between the normal and non-uniform
(Fulde-Ferrell-Larkin-Ovchinnikov) superconducting state in quasi
two-dimensional d-wave superconductors at finite temperature. We obtain an
appropriate Ginzburg-Landau theory for this transition, in which the
fluctuation spectrum of the order parameter has a set of minima at non-zero
momenta. The momentum shell renormalization group procedure combined with
dimensional expansion is then applied to analyze the phase structure of the
theory. We find that all fixed points have more than one relevant directions,
indicating the transition is of the fluctuation-driven first order type for
this universality class.Comment: 5 page
Josephson Effect in Fulde-Ferrell-Larkin-Ovchinnikov Superconductors
Due to the difference in the momenta of the superconducting order parameters,
the Josephson current in a Josephson junction between a
Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) superconductor and a conventional BCS
superconductor is suppressed. We show that the Josephson current may be
recovered by applying a magnetic field in the junction. The field strength and
direction at which the supercurrent recovery occurs depend upon the momentum
and structure of the order parameter in the FFLO state. Thus the Josephson
effect provides an unambiguous way to detect the existence of an FFLO state,
and to measure the momentum of the order parameter.Comment: 4 pages with one embedded eps figur