Recent advances in the energy resolution and cryogenic techniques used in photoemission spectroscopy have enabled us to directly observe the superconducting electronic structure of superconductors with a relatively lower transition temperature (low-Tc). In this paper, we report photoemission results on low-Tc superconductors measured with an ultrahigh-resolution low-temperature photoemission spectrometer. The result of Nb3Al exhibits a superconducting gap and a phonon-induced peak-dip-hump structure characteristic of the strong-coupling superconducting spectral function. From measurements of Ba0.67K0.33BiO3, we observe isotropic s-wave superconducting gap opening below Tc as well as depletion of intensity near the Fermi level above Tc, which can be attributed to a phonon-induced pseudogap. We will compare these photoemission results with those of high-Tc superconductors.
- Photoemission spectroscopy
- Superconducting gap
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Energy Engineering and Power Technology
- Electrical and Electronic Engineering