High-resolution and analytical electron microscopy (HREM and AEM, respectively) techniques have been utilized to probe the submicroscopic details of crystallography, chemistry and electronic structure of HgBa2CuO4+δ, a recently discovered single- layer copper-oxide superconductor. Core loss EELS analysis of O K edge reveals a pre-edge similar to many p-type doped copper oxide superconductors, while a free change carrier plasmon has been identified with low loss EELS. It is discovered that the delocalized hole carrier concentration in a lower-Tc sample (argon annealed), as inferred from oscillator strengths, is about ≈60% of that of a fully oxygenated sample, which has a higher Tc. It is also discovered that there is a strong excitation just above the delocalized hole state (by ≈ 2 eV) in both lower- and higher-Tc samples. These observations are compared with other cuprate superconductors.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Energy Engineering and Power Technology
- Electrical and Electronic Engineering