Extremely strong coupling superconductivity of heavy-electrons in two-dimensions
Fig. 1: Transmission elctron microscope image of the superlattice of alternating layers of one unit-cell-thick magnetic CeCoIn5 and five unit-cell-thick nonmagnetic YbCoIn5.
The ultimately strong electron-electron interaction in metal is realized in the so-called heavy-fermion compound containing rare earth elements, in which the electron effective mass is enhanced by a few hundred times the free electron mass.
The group of Yuta Mizukami, Yuji Matsuda and Takasada Shibauchi in Department of Physics and Takahito Terashima in Research Center for Low Temperature and Materials Sciences, has succeeded in achieving the first experimental realization of ‘heavy superconducting electrons’ in a two-dimensional lattice, which were obtained by fabricating heterostructures unavailable in nature.
Superlattices with heavy-fermion CeCoIn5 and nonmagnetic YbCoIn5 layers are grown alternately by the molecular-beam-epitaxy technique (Fig. 1). Superconductivity is observed even in superlattice with one-unit-cell thick CeCoIn5 layers, demonstrating a heavy-electron superconductivity with purely two-dimensional electron correlations.
Fig. 2: Superconducting properties of CeCoIn5/YbCoIn5 superlattices. Left: Temperature dependence of the resistivity. n is the number of CeCoIn5 layers. Right: Thickness dependence of the superconducting transition temperature and the superconducting coupling strength, represented by 2Δ/kBTc. In most superconductors, the 2Δ/kBTc value is close to 3.5.
Most remarkably, the superconductivity in superlattices persists under significantly higher reduced magnetic fields than in the bulk, implying that the force ("glue") holding together the superconducting electron pairs takes on an extremely strong coupled nature as a result of two-dimensionalization (Fig. 2) -- a situation reminiscent of the high-Tc cuprates.More information: The article, " Extremely strong coupling superconductivity in artificial two-dimensional Kondo lattices " by Y. Mizukami, H. Shishido, T. Shibauchi, M. Shimozawa, S. Yasumoto, D. Watanabe, M.Yamashita, H. Ikeda, T. Terashima, H. Kontani, Y. Matsuda was published in Nature Physics. Published online 09 October 2011. DOI:10.1038/nphys2112
Provided by Kyoto University
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Art applied his theory mainly to biology (heart cells, Malaysian fireflies, etc.) More recently, Strogatz and Mirollo have stressed that it must apply to physics as well, but physicists have been slow to accept the invitation.
A two dimensional system of oscillators will synchronize oscillations much more easily than a three dimensional system. Cooper pairs may be understood as being paired exactly antisnchronously, as to their orbit and spin, both of which are quantum oscillations. Quanta are limit cycles.
A particular virtue of this theory--perfectly synchronized oscillations--is that it may explain all types of superconductivity.
Oct 22, 2011
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That is the only question and measure of any SC theory.
Anything else is lip service.
Oct 22, 2011
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So that the highest temperature superconductor can be made of layers with oxidized atoms in a high oxidation state surrounded with many layers of inert oxides. Such materials enable to reach temperatures of superconductor transition well above 20°C.
http://www.superc.../20C.htm
Oct 22, 2011
Rank: 1 / 5 (1)
Oct 22, 2011
Rank: 1 / 5 (1)
http://www.newsci...rch.html
I do believe, such electrons could be attracted to surface of insulator with external electric charge, too.
http://www.aether...ctor.gif
So, if we surround well insulated wire with positive charge, the electrons from outside will get attracted to it and they will cover the surface of insulator with superconductive layer of electrons. The only problem is, how to create the sufficiently compact insulator layer, resistant to dielectric breakthrough.