We have performed high-resolution photoemission spectroscopy on MgB2 and observed opening of a superconducting gap with a narrow coherent peak. We found that the superconducting gap is s-like with the gap value of 4.5 meV at 15 K. The temperature dependence (15 - 40 K) of gap value follows well the BCS form, suggesting that 2Delta/kBTc at T=0 is about 3. No pseudogap behavior is observed in the normal state. The present results strongly suggest that MgB2 is categorized into a phonon-mediated BCS superconductor in the weak-coupling regime.
@article{arxiv.cond-mat/0103079,
title = {High-Resolution Photoemission Study of MgB2},
author = {T. Takahashi and T. Sato and S. Souma and T. Muranaka and J. Akimitsu},
journal= {arXiv preprint arXiv:cond-mat/0103079},
year = {2009}
}
Comments
3 pages, 3 figures, accepted in Physical Review Letters