Correlation of tunneling spectra with surface nanomorphology and doping in thin films
Racah Institute of Physics, The Hebrew University - Jerusalem 91904, Israel
2 Department of Physics, Technion-Israel Institute of Technology, Haifa 32000, Israel
Corresponding author: firstname.lastname@example.org
Accepted: 29 March 2001
Tunneling spectra measured on thin epitaxial 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.
PACS: 74.50.+r – Proximity effects, weak links, tunneling phenomena, and Josephson effects / 74.72.Bk – Y-based cuprates / 74.80.-g – Spatially inhomogeneous structures
© EDP Sciences, 2001