title: Localized superconductivity in the quantum-critical region of the disorder-driven superconductor-insulator transition in TiN thin films.
abstract: We investigate low-temperature transport properties of thin TiN superconducting films in the vicinity of the disorder-driven superconductor-insulator transition. In a zero magnetic field, we find an extremely sharp separation between superconducting and insulating phases, evidencing a direct superconductor-insulator transition without an intermediate metallic phase. At moderate temperatures, in the insulating films we reveal thermally activated conductivity with the magnetic field-dependent activation energy. At very low temperatures, we observe a zero-conductivity state, which is destroyed at some depinning threshold voltage V{T}. These findings indicate the formation of a distinct collective state of the localized Cooper pairs in the critical region at both sides of the transition.
authors.affiliation: Institute of Semiconductor Physics, 630090 Novosibirsk, Russia.
authors.forename: T I
authors.initials: TI
authors.lastname: Baturina
authors.forename: A Yu
authors.initials: AY
authors.lastname: Mironov
authors.forename: V M
authors.initials: VM
authors.lastname: Vinokur
authors.forename: M R
authors.initials: MR
authors.lastname: Baklanov
authors.forename: C
authors.initials: C
authors.lastname: Strunk