We report here the results of scanning tunneling spectroscopy experiments performed on hole-doped NdBa2Cu3O7- δ single crystals of Tc values of 76 K, 93.5 K and 95.5 K. The energy gaps are observed to be increasing with decreasing Tc values. The coherence peaks are asymmetric with the peaks at the filled states being larger than those at the empty ones. The asymmetry increases with decreasing T c. The observed asymmetry and its Tc-dependence can be explained by considering the Mott insulating nature of the material at the undoped state.
ASJC Scopus subject areas
- General Physics and Astronomy