Correlation of tunneling spectra with surface nano-morphology and doping in thin YBa2Cu3O7-delta films
arXiv:cond-mat/0103581 · doi:10.1209/epl/i2001-00368-1
Abstract
Tunneling spectra measured on thin epitaxial YBa2Cu3O7-delta films are found to exhibit strong spatial variations, showing U and V-shaped gaps as well as zero bias conductance peaks typical of a d-wave superconductor. A full correspondence is found between the tunneling spectra and the surface morphology down to a level of a unit-cell step. Splitting of the zero bias conductance peak is seen in optimally-doped and overdoped films, but not in the underdoped ones, suggesting that there is no transition to a state of broken time reversal symmetry in the underdoped regime
accepted to epl