title: Model evidence of a superconducting state with a full energy gap in small cuprate islands.
abstract: We investigate subdominant order parameters stabilizing at low temperatures in nanoscale high-T(c) cuprate islands, motivated by the recent observation of a fully gapped state in nanosized YBa(2)Cu(3)O(7-δ) [D. Gustafsson et al., Nature Nanotech. 8, 25 (2013)]. Using complementary quasiclassical and tight-binding Bogoliubov-de Gennes methods, we show on distinctly different properties dependent on the symmetry being d(x(2)-y(2))+is or d(x(2)-y(2))+id(xy). We find that a surface-induced d(x(2)-y(2))+is phase creates a global spectroscopic gap which increases with an applied magnetic field, consistent with experimental observation.
authors.affiliation: Department of Physics and Astronomy, Uppsala University, Box 516, S-751 20 Uppsala, Sweden.
authors.forename: Annica M
authors.initials: AM
authors.lastname: Black-Schaffer
authors.forename: Dmitri S
authors.initials: DS
authors.lastname: Golubev
authors.forename: Thilo
authors.initials: T
authors.lastname: Bauch
authors.forename: Floriana
authors.initials: F
authors.lastname: Lombardi
authors.forename: Mikael
authors.initials: M
authors.lastname: Fogelström