Possible nodal superconducting gap in Fe1+y(Te 1-xSex) single crystals from ultralow temperature penetration depth measurements

Andrei Diaconu, Catalin Martin, Jin Hu, Tijiang Liu, Bin Qian, Zhiqiang Mao, Leonard Spinu

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

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).

Original languageEnglish (US)
Article number104502
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume88
Issue number10
DOIs
StatePublished - Sep 3 2013

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depth measurement
cryogenic temperature
penetration
Single crystals
single crystals
tunnel diodes
Tunnel diode oscillators
temperature dependence
Temperature
radio frequencies
oscillators
exponents
temperature

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

Cite this

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title = "Possible nodal superconducting gap in Fe1+y(Te 1-xSex) single crystals from ultralow temperature penetration depth measurements",
abstract = "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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Possible nodal superconducting gap in Fe1+y(Te 1-xSex) single crystals from ultralow temperature penetration depth measurements. / Diaconu, Andrei; Martin, Catalin; Hu, Jin; Liu, Tijiang; Qian, Bin; Mao, Zhiqiang; Spinu, Leonard.

In: Physical Review B - Condensed Matter and Materials Physics, Vol. 88, No. 10, 104502, 03.09.2013.

Research output: Contribution to journalArticle

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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