https://doi.org/10.1140/epjb/e2009-00198-y
Surface of underdoped YBa2Cu3O7-δ as revealed by STM/STS
1
Institute of Experimental Physics, University of Wroclaw, 50-204 Wroclaw, Poland
2
Leibniz-Institute for Solid State and Materials Research, IFW-Dresden, 01171 Dresden, Germany
3
Max Planck Institute for Solid State Research, Stuttgart, Germany
Corresponding author: a gurbanik@ifd.uni.wroc.pl
Received:
26
October
2008
Revised:
29
March
2009
Published online:
9
June
2009
We performed scanning tunneling microscopy and spectroscopy on untwinned crystals of underdoped YBa2Cu3O7-δ at δ = 0.4. A comprehensive statistical analysis of our topographic data indicates a doping dependent cleaving behavior of this material. We find in particular that at δ = 0.4 the material primarily cleaves in multiples of one unit cell along the c-axis with a high corrugation of the topmost layer. Our data suggest that the low temperature cleaving mainly results in a disruption of the CuO chain layers involving a redistribution of the layer atoms onto the two cleaving planes. In a few instances, fractional step heights (in terms of the c-axis lattice constant) are observed as well. Scanning tunneling spectroscopy reveals that such fractional steps connect surfaces which differ significantly in their tunneling conductance.
PACS: 74.72.-h – Cuprate superconductors / 74.72.Bk – Y-based cuprates / 68.37.Ef – Scanning tunneling microscopy
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2009