title: Novel route to a finite center-of-mass momentum pairing state for superconductors: A current-driven Fulde-Ferrell-Larkin-Ovchinnikov state.
abstract: The previously studied Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state is stabilized by a magnetic field via the Zeeman coupling in spin-singlet superconductors. Here we suggest a novel route to achieve nonzero center-of-mass momentum pairing states in superconductors with Fermi surface nesting. We investigate two-dimensional superconductors under a uniform external current, proportional to a finite pair momentum of q(e). We find that an FFLO state with a spontaneous pair momentum of q(s) is stabilized above a certain critical current that depends on the direction of the external current. A finite q(s) arises in order to make the total pair-momentum of q(t)(=q(s) + q(e)) perpendicular to the nesting vector, which is independent of spin states of Cooper pairs. We also discuss experimental signatures of the FFLO state.
authors.affiliation: Department of Physics, University of Toronto, Toronto, Ontario M5S 1A7, Canada. hdoh@physics.utoronto.ca
authors.forename: Hyeonjin
authors.initials: H
authors.lastname: Doh
authors.forename: Matthew
authors.initials: M
authors.lastname: Song
authors.forename: Hae-Young
authors.initials: HY
authors.lastname: Kee