Influence of disorder on the local density of states in high- T(c) superconducting thin films
Using a low temperature scanning tunneling microscope in the spectroscopic mode, we find that the disorder in a Bi(2)Sr(2)CaCu(2)O(8+delta) thin film modifies dramatically the quasiparticle local density of states. Small, but well-defined superconducting regions, coexisting with dominating semiconducting areas, show well-pronounced gap structures, similar to those observed previously in high-quality single crystals. Surprisingly, between these two regions, the detailed shape of the quasiparticle spectrum is virtually identical to the pseudogap previously observed at temperatures T>T(c), or in the vortex core, at 4.2 K. Thus, the role of the disorder in destroying the superconducting phase is comparable to that of the magnetic field or thermal fluctuations.
Cren
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Groupe de Physique des Solides, Universites Paris 7 et Paris 6, Unite Mixte de Recherche C.N.R.S. (UMR 75 88), 2 Place Jussieu, 75251 Paris Cedex 5, France.
Roditchev
D
Sacks
W
Klein
J
Moussy
J
Deville-Cavellin
C
Lagues
M