TY - JOUR
T1 - London penetration depth and superfluid density of single-crystalline Fe1+y ( Te1-x Sex ) and Fe1+y ( Te1-x Sx )
AU - Kim, H.
AU - Martin, C.
AU - Gordon, R. T.
AU - Tanatar, M. A.
AU - Hu, J.
AU - Qian, B.
AU - Mao, Z. Q.
AU - Hu, Rongwei
AU - Petrovic, C.
AU - Salovich, N.
AU - Giannetta, R.
AU - Prozorov, R.
PY - 2010/5/10
Y1 - 2010/5/10
N2 - The in-plane London penetration depth, λ (T), was measured in single crystals of the iron-chalcogenide superconductors Fe1.03 (Te 0.63 Se0.37) and Fe1.06 (Te0.88 S0.14) by using a radio-frequency tunnel diode resonator. Similar to the iron-arsenides and in stark contrast to the iron-phosphides, iron-chalcogenides exhibit a nearly quadratic temperature variation of λ (T) at low temperatures. The absolute value of the penetration depth in the T→0 limit was determined for Fe1.03 (Te0.63 Se 0.37) by using an Al coating technique, giving λ (0) 560±20 nm. The superfluid density ρs (T) = λ2 (0) / λ2 (T) was fitted with a self-consistent two-gap γ model. While two different gaps are needed to describe the full-range temperature variation in ρs (T), a nonexponential low-temperature behavior requires pair-breaking scattering, and therefore an unconventional (e.g., s± or nodal) order parameter.
AB - The in-plane London penetration depth, λ (T), was measured in single crystals of the iron-chalcogenide superconductors Fe1.03 (Te 0.63 Se0.37) and Fe1.06 (Te0.88 S0.14) by using a radio-frequency tunnel diode resonator. Similar to the iron-arsenides and in stark contrast to the iron-phosphides, iron-chalcogenides exhibit a nearly quadratic temperature variation of λ (T) at low temperatures. The absolute value of the penetration depth in the T→0 limit was determined for Fe1.03 (Te0.63 Se 0.37) by using an Al coating technique, giving λ (0) 560±20 nm. The superfluid density ρs (T) = λ2 (0) / λ2 (T) was fitted with a self-consistent two-gap γ model. While two different gaps are needed to describe the full-range temperature variation in ρs (T), a nonexponential low-temperature behavior requires pair-breaking scattering, and therefore an unconventional (e.g., s± or nodal) order parameter.
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U2 - 10.1103/PhysRevB.81.180503
DO - 10.1103/PhysRevB.81.180503
M3 - Article
AN - SCOPUS:77955450866
SN - 1098-0121
VL - 81
JO - Physical Review B - Condensed Matter and Materials Physics
JF - Physical Review B - Condensed Matter and Materials Physics
IS - 18
M1 - 180503
ER -