Nodal superconductivity in isovalently substituted SrFe2(As1−xPx)2 pnictide superconductor at the optimal doping x=0.35

J. Murphy; C. P. Strehlow; K. Cho; M. A. Tanatar; N. Salovich; R. W. Giannetta; T. Kobayashi; S. Miyasaka; S. Tajima; R. Prozorov

doi:10.1103/PhysRevB.87.140505

Nodal superconductivity in isovalently substituted SrFe2(As1−xPx)2 pnictide superconductor at the optimal doping x=0.35

J. Murphy, C. P. Strehlow, K. Cho, M. A. Tanatar, N. Salovich, R. W. Giannetta, T. Kobayashi, S. Miyasaka, S. Tajima, R. Prozorov

DOI 10.1103/PhysRevB.87.140505 · Physical Review B

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Abstract

Temperature-dependent London penetration depth λ(T) was measured in optimally doped x=0.35, as-grown [Tc≈25 K, RRR=ρ(300K)/ρ(Tc)=4.5], and annealed (Tc≈35 K, RRR=6.4) single crystals of SrFe2(As1−xPx)2 iron-based superconductor. Annealing increases the residual resistivity ratio (RRR) and decreases the absolute value of the London penetration depth from λ(0)=300±10 nm in the as-grown sample to λ(0)=275±10 nm. At low temperatures, λ(T)∼T indicating a superconducting gap with line nodes. Analysis of the full-temperature range superfluid density is consistent with the line nodes, but differs from the simple single-gap d wave. The observed behavior is very similar to that of BaFe2(As1−xPx)2, showing that isovalently substituted pnictides are inherently different from the charge-doped materials.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
SrFe2(As1-xPx)2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	25	Pressure not reported	unknown
SrFe2(As1-xPx)2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	35	Pressure not reported	unknown
SrFe2(As1-xPx)2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	27	Pressure not reported	unknown
SrFe2(As1-xPx)2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	34.8	Pressure not reported	unknown
BaFe2As2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	38	Pressure not reported	unknown
BaFe2As2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	24	Pressure not reported	unknown
BaFe2As2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	31	Pressure not reported	unknown