Tunneling spectroscopy of the superconducting gap in MgB2

Toshikazu Ekino; Tomoaki Takasaki; Takahiro Muranaka; Jun Akimitsu; Hironobu Fujii

Tunneling spectroscopy of the superconducting gap in MgB₂

Toshikazu Ekino, Tomoaki Takasaki, Takahiro Muranaka, Jun Akimitsu, Hironobu Fujii

Research output: Contribution to journal › Article › peer-review

Abstract

The tunneling technique with a break junction has been applied to investigate the multiple superconducting gaps in MgB₂. The observed gap features can be explained by combining inherent and induced order parameters. The largest gap of Δ = 9-10 meV corresponds to a very strong-coupling ratio 2Δ/k_BT_c = 5-6. Upon warming, this gap decreases in accordance with the BCS dependence, while the smaller gaps reduce faster than that but persist up to T_c. Therefore, the smallest gap of Δ = 2-2.5 meV gives 2Δ/k_BT_c = 1.2-1.5. The magnetic field can distinguish the behavior of the gap. The extrapolated highest gap-closing field for the largest gap agrees with the upper-critical field, thereby indicating that this gap is predominant to MgB₂.

Original language	English
Article number	094504
Pages (from-to)	945041-945046
Number of pages	6
Journal	Physical Review B - Condensed Matter and Materials Physics
Volume	67
Issue number	9
Publication status	Published - Mar 1 2003
Externally published	Yes

ASJC Scopus subject areas

Electronic, Optical and Magnetic Materials
Condensed Matter Physics

Cite this

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abstract = "The tunneling technique with a break junction has been applied to investigate the multiple superconducting gaps in MgB2. The observed gap features can be explained by combining inherent and induced order parameters. The largest gap of Δ = 9-10 meV corresponds to a very strong-coupling ratio 2Δ/kBTc = 5-6. Upon warming, this gap decreases in accordance with the BCS dependence, while the smaller gaps reduce faster than that but persist up to Tc. Therefore, the smallest gap of Δ = 2-2.5 meV gives 2Δ/kBTc = 1.2-1.5. The magnetic field can distinguish the behavior of the gap. The extrapolated highest gap-closing field for the largest gap agrees with the upper-critical field, thereby indicating that this gap is predominant to MgB2.",

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AU - Fujii, Hironobu

PY - 2003/3/1

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N2 - The tunneling technique with a break junction has been applied to investigate the multiple superconducting gaps in MgB2. The observed gap features can be explained by combining inherent and induced order parameters. The largest gap of Δ = 9-10 meV corresponds to a very strong-coupling ratio 2Δ/kBTc = 5-6. Upon warming, this gap decreases in accordance with the BCS dependence, while the smaller gaps reduce faster than that but persist up to Tc. Therefore, the smallest gap of Δ = 2-2.5 meV gives 2Δ/kBTc = 1.2-1.5. The magnetic field can distinguish the behavior of the gap. The extrapolated highest gap-closing field for the largest gap agrees with the upper-critical field, thereby indicating that this gap is predominant to MgB2.

AB - The tunneling technique with a break junction has been applied to investigate the multiple superconducting gaps in MgB2. The observed gap features can be explained by combining inherent and induced order parameters. The largest gap of Δ = 9-10 meV corresponds to a very strong-coupling ratio 2Δ/kBTc = 5-6. Upon warming, this gap decreases in accordance with the BCS dependence, while the smaller gaps reduce faster than that but persist up to Tc. Therefore, the smallest gap of Δ = 2-2.5 meV gives 2Δ/kBTc = 1.2-1.5. The magnetic field can distinguish the behavior of the gap. The extrapolated highest gap-closing field for the largest gap agrees with the upper-critical field, thereby indicating that this gap is predominant to MgB2.

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Tunneling spectroscopy of the superconducting gap in MgB₂

Abstract

ASJC Scopus subject areas

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