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Direct evidence for a multiple superconducting gap in MgB2 from high-resolution photoemission spectroscopy

S. Tsuda·T. Yokoya·T. Kiss·Y. Takano·K. Togano·H. Kitou·H. Ihara·S. Shin
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Abstract

We study the new binary intermetallic superconductor MgB2 using high-resolution photo-emission spectroscopy. The superconducting-state spectrum measured at 5.4 K shows a coherent peak with a shoulder structure, in sharp contrast to that expected from a simple isotropic-gap opening. The spectrum can be well reproduced using the weighted sum of two Dynes functions with the gap sizes of 1.7 and 5.6 meV. Temperature-dependent study shows that both gaps close at the bulk transition temperature. These results provide spectroscopic evidence for a multiple gap of MgB2.

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S. Tsuda, T. Yokoya, T. Kiss, Y. Takano, K. Togano, H. Kitou, H. Ihara, S. Shin. 2001-04-25. Direct evidence for a multiple superconducting gap in MgB2 from high-resolution photoemission spectroscopy. https://doi.org/10.1103/physrevlett.87.177006

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