| Autor: |
Naidyuk, Yu. G., Yanson, I. K., Tyutrina, L. V., Bobrov, N. L., Chubov, P. N., Kang, W. N., Kim, Hyeong-Jin, Choi, Eun-Mi, Lee, Sung-Ik |
| Předmět: |
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| Zdroj: |
JETP Letters; 3/10/2002, Vol. 75 Issue 5, p238, 4p |
| Abstrakt: |
We have analyzed about a hundred voltage-dependent differential resistance dV/dI(V) curves of metallic point contacts between c-axis-oriented MgB[sub 2] thin film and Ag, which exhibit clear Andreev reflection features connected with the superconducting gap. About one half of the curves show the presence of a second larger gap. The histogram of the double gap distribution reveals distinct maxima at 2.4 and 7 meV, while curves with single-gap features result in a more broad maximum at 3.5 meV. The double-gap distribution is in qualitative agreement with the distribution of gap values over the Fermi surface calculated by H.J. Choi etal. (cond-mat/0111183). The data unequivocally show the presence of two gaps: Δ[sub S] = 2.45±0.15 meV and Δ[sub L] = 7.0±0.45 meV in MgB[sub 2] with the gap ratio Δ[sub L]/Δ[sub S] = 2.85±0.15. Our observations further prove a widely discussed multigap scenario for MgB[sub 2], where two distinct gaps are seen in the clean limit, while a single averaged gap is present in the dirty one. © 2002 MAIK “Nauka / Interperiodica”. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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