title: Metal-bosonic insulator-superconductor transition in boron-doped granular diamond.
abstract: In a variety of superconductors, mostly in two-dimensional (2D) and one-dimensional (1D) systems, the resistive superconducting transition R(T) demonstrates in many cases an anomalous narrow R(T) peak just preceding the onset of the superconducting state R=0 at T(c). The amplitude of this R(T) peak in 1D and 2D systems ranges from a few up to several hundred percent. In three-dimensional (3D) systems, however, the R(T) peak close to T(c) is rarely observed, and it reaches only a few percent in amplitude. Here we report on the observation of a giant (∼1600%) and very narrow (∼1  K) resistance peak preceding the onset of superconductivity in heavily boron-doped diamond. This anomalous R(T) peak in a 3D system is interpreted in the framework of an empirical model based on the metal-bosonic insulator-superconductor transitions induced by a granularity-correlated disorder in heavily doped diamond.
authors.affiliation: INPAC-Insititute for Nanoscale Physics and Chemistry, KU Leuven, Celestijnenlaan 200D, B-3001 Leuven, Belgium.
authors.forename: Gufei
authors.initials: G
authors.lastname: Zhang
authors.affiliation: School of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom.
authors.forename: Monika
authors.initials: M
authors.lastname: Zeleznik
authors.affiliation: INPAC-Insititute for Nanoscale Physics and Chemistry, KU Leuven, Celestijnenlaan 200D, B-3001 Leuven, Belgium.
authors.forename: Johan
authors.initials: J
authors.lastname: Vanacken
authors.affiliation: School of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom.
authors.forename: Paul W
authors.initials: PW
authors.lastname: May
authors.affiliation: INPAC-Insititute for Nanoscale Physics and Chemistry, KU Leuven, Celestijnenlaan 200D, B-3001 Leuven, Belgium.
authors.forename: Victor V
authors.initials: VV
authors.lastname: Moshchalkov