Dresden 2006 – scientific programme
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TT: Tiefe Temperaturen
TT 7: Superconductivity & Solids At Low Temperature - Poster Session
TT 7.18: Poster
Monday, March 27, 2006, 14:00–17:45, P1
Nanometer-scale superconducting domains observed on NdBa2Cu3O7−δ — •Pintu Das1, Dirk Mautes1, Michael R. Koblischka1, Thomas Wolf2, and Uwe Hartmann1 — 1Institute of Experimental Physics, University of Saarbruecken, D-66041 Saarbruecken, Germany — 2Forschungzentrum Karlsruhe GmbH, Instiitute of Solid State Physics, D-76021 Karlsruhe, Germany
In understanding high temperature superconductivity, the recent focus is at the local-scale electronic modulation and its influence towards superconductivity in general. The granular structure and atomic-scale modulation of the density of states in Bi2Sr2CaCu2O8+δ have been observed [1,2]. Here we report Scanning Tunneling Spectroscopic (STS) results obtained on the (ab) plane of a slightly underdoped NdBa2Cu3O7−δ (Tc= 93.5 K) twinned single crystals at 4.2 K. Recent results proved that the NdBCO surface is highly clean and stable in air, showing atomic resolution at room temperature [3]. We used the STS imaging technique to study the electronic inhomogeneity and we observe that there are superconducting domains of ∼ 3 nm length scale separated by nonsuperconducting regions, similar to that observed in Bi2Sr2CaCu2O8+δ. In the superconducting domains, the size of the energy gap spatially varies from ∼ 16 meV to ∼ 44 meV. The average gap size is found to be ∼ 22 meV. We discuss these data and the possible origin of the inhomogeneous electronic structure of the respective materials.
[1] Lang et al., Nature 415, 412 (2002)
[2] McElroy et al., Nature 422, 592 (2003)
[3] Ting et al., Appl. Phys. Lett. 72, 2035 (1998)