title: Local measurement of the superfluid density in the pnictide superconductor Ba(Fe(1-x)Co(x))(2)As(2) across the superconducting dome.
abstract: We measure the penetration depth λab(T) in Ba(Fe(1-x)Co(x))(2)As(2) using local techniques that do not average over the sample. The superfluid density ρs(T) ≡ 1/λab(T)2 has three main features. First, ρs (T = 0) falls sharply on the underdoped side of the dome. Second, λab(T) is flat at low T at optimal doping, indicating fully gapped superconductivity, but varies more strongly in underdoped and overdoped samples, consistent with either a power law or a small second gap. Third, ρs (T) varies steeply near Tc for optimal and underdoping. These observations are consistent with an interplay between magnetic and superconducting phases.
authors.affiliation: Stanford Institute for Materials and Energy Science, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA.
authors.forename: Lan
authors.initials: L
authors.lastname: Luan
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Lippman
authors.forename: Clifford W
authors.initials: CW
authors.lastname: Hicks
authors.forename: Julie A
authors.initials: JA
authors.lastname: Bert
authors.forename: Ophir M
authors.initials: OM
authors.lastname: Auslaender
authors.forename: Jiun-Haw
authors.initials: JH
authors.lastname: Chu
authors.forename: James G
authors.initials: JG
authors.lastname: Analytis
authors.forename: Ian R
authors.initials: IR
authors.lastname: Fisher
authors.forename: Kathryn A
authors.initials: KA
authors.lastname: Moler
mesh_terms: D001151:Arsenic / Q000737:chemistry*; D001464:Barium / Q000737:chemistry*; D003035:Cobalt / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D013696:Temperature
chemical_list: D001464:Barium; D003035:Cobalt; D007501:Iron; D001151:Arsenic