990 research outputs found
Superconducting junctions from non-superconducting doped CuO layers
The theoretical approach proposed recently for description of redistribution
of electronic charge in multilayered selectively doped systems is modified for
a system with finite number of layers. A special attention is payed to the case
of a finite heterostructure made of copper-oxide layers which are all
non-superconducting (including non-conducting) because of doping levels being
beyond the well-known characteristic interval for superconductivity. Specific
finite structures and doping configurations are proposed to obtain atomically
thin superconducting heterojunctions of different compositions.Comment: 4 pages, 3 figures, two bibliography references were update
Fluctuating order parameter in doped cuprate superconductors
We discuss static fluctuations of the d-wave superconducting order parameter
in CuO planes, due to quasiparticle scattering by charged dopants.
The analysis of two-particle anomalous Green functions at permits to
estimate the mean-square fluctuation ,
averaged in random dopant configurations, to the lowest order in doping level
. Since is found to saturate with growing doping level while
remains to grow, this can explain the collapse of at overdoping.
Also we consider the spatial correlations for
order parameter in different points of the plane.Comment: RevTex4, 3 pages, to be published in Proceedings of New3SC-4
International Conference, San Diego, California, January 15-21, 200
Boundary Friction on Molecular Lubricants: Rolling Mode?
A theoretical model is proposed for low temperature friction between two
smooth rigid solid surfaces separated by lubricant molecules, admitting their
deformations and rotations. Appearance of different modes of energy dissipation
(by ''rocking'' or ''rolling'' of lubricants) at slow relative displacement of
the surfaces is shown to be accompanied by the stick-and-slip features and
reveals a non-monotonic (mean) friction force {\it vs} external loadComment: revtex4, 4 pages, 5 figure
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