Local Measurement of the Superfluid Density in the Pnictide Superconductor Ba(Fe1−xCox)2As2 across the Superconducting Dome

Lan Luan; Thomas M. Lippman; Clifford W. Hicks; Julie A. Bert; Ophir M. Auslaender; Jiun-Haw Chu; James G. Analytis; Ian R. Fisher; Kathryn A. Moler

doi:10.1103/PhysRevLett.106.067001

Local Measurement of the Superfluid Density in the Pnictide Superconductor Ba(Fe1−xCox)2As2 across the Superconducting Dome

Lan Luan, Thomas M. Lippman, Clifford W. Hicks, Julie A. Bert, Ophir M. Auslaender, Jiun-Haw Chu, James G. Analytis, Ian R. Fisher, Kathryn A. Moler

DOI 10.1103/PhysRevLett.106.067001 · Physical Review Letters

T1

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Abstract

We measure the penetration depth λab(T) in Ba(Fe1−xCox)2As2 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.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
Ba(Fe1-xCox)2As2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown