We study the single particle density of states (DOS) across the superconducting transition (Tc = 31 K) in single-crystal Ba0.67K0.33BiO3 using ultrahigh resolution angle-integrated photoemission spectroscopy. The superconducting gap opens with a pile-up in the DOS, Delta(5.3 K) = 5.2 meV and 2Delta(0)/kBTc = 3.9. In addition, we observe a pseudogap below and above Tc, occurring as a suppression in intensity over an energy scale up to the breathing mode phonon(~ 70 meV). The results indicate electron-phonon coupling induces a pseudogap in Ba0.67K0.33BiO3.
@article{arxiv.cond-mat/0106039,
title = {Electron-phonon coupling induced pseudogap and the superconducting transition in Ba0.67K0.33BiO3},
author = {A. Chainani and T. Yokoya and T. Kiss and S. Shin and T. Nishio and H. Uwe},
journal= {arXiv preprint arXiv:cond-mat/0106039},
year = {2009}
}
Comments
5 pages with 4 figures, submitted to Phys. Rev. Lett