The Fermi surface and superconducting gap of MgB2 have been studied by angle-resolved photoemission spectroscopy. Two Fermi surfaces composed of the σ band and the π band are clearly observed without contaminated by the "surface-derived" band. The high-resolution photoemission spectra show that superconducting gaps with values of 5.5 and 2.2 meV open on the σ band and the π band, respectively, both of which close at the bulk transition temperature (Tc). This result provides an experimental evidence for the two-band superconductivity on MgB2 and, moreover, validates the role of momentum-dependent electron-phonon coupling as the origin of multiple-gap superconductivity as well as the high transition temperature (Tc) of MgB2.
- Superconducting gap
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Energy Engineering and Power Technology
- Electrical and Electronic Engineering