TY - JOUR
T1 - Possible nodal superconducting gap in Fe1+y(Te 1-xSex) single crystals from ultralow temperature penetration depth measurements
AU - Diaconu, Andrei
AU - Martin, Catalin
AU - Hu, Jin
AU - Liu, Tijiang
AU - Qian, Bin
AU - Mao, Zhiqiang
AU - Spinu, Leonard
PY - 2013/9/3
Y1 - 2013/9/3
N2 - Using a radio-frequency tunnel diode oscillator technique, we measured the temperature dependence of the in-plane London penetration depth Δλab(T) in Fe1+y(Te1-xSe x) single crystals, down to temperatures as low as 50 mK. A significant number of samples, with nominal Se concentrations x=0.36, 0.40, 0.43, and 0.45, respectively, were studied and in many cases we found that Δλab(T) shows an upturn below 0.7 K, indicative of a paramagnetic-type contribution. After subtracting the magnetic background, the low-temperature behavior of penetration depth is best described by a power law with exponent n≈2 and with no systematic dependence on the Se concentration. Most importantly, in the limit of T→0, in some samples we observed a narrow region of linear temperature dependence of penetration depth, suggestive of nodes in the superconducting gap of Fe1+y(Te1-xSe x).
AB - Using a radio-frequency tunnel diode oscillator technique, we measured the temperature dependence of the in-plane London penetration depth Δλab(T) in Fe1+y(Te1-xSe x) single crystals, down to temperatures as low as 50 mK. A significant number of samples, with nominal Se concentrations x=0.36, 0.40, 0.43, and 0.45, respectively, were studied and in many cases we found that Δλab(T) shows an upturn below 0.7 K, indicative of a paramagnetic-type contribution. After subtracting the magnetic background, the low-temperature behavior of penetration depth is best described by a power law with exponent n≈2 and with no systematic dependence on the Se concentration. Most importantly, in the limit of T→0, in some samples we observed a narrow region of linear temperature dependence of penetration depth, suggestive of nodes in the superconducting gap of Fe1+y(Te1-xSe x).
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U2 - 10.1103/PhysRevB.88.104502
DO - 10.1103/PhysRevB.88.104502
M3 - Article
AN - SCOPUS:84884891867
SN - 1098-0121
VL - 88
JO - Physical Review B - Condensed Matter and Materials Physics
JF - Physical Review B - Condensed Matter and Materials Physics
IS - 10
M1 - 104502
ER -