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Do pairs exist above Tc
A S Alexandrov,N F Mott +1 more
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TLDR
In this article, the main difficulties of superconductivity in high-Tc oxides and in doped fullerenes are analysed in the light of some experimental observations paying special attention to those in which pairs exist or are claimed to be observed above Tc.Abstract:
Theories describing superconductivity in high-Tc oxides and in doped fullerenes can be placed in four categories: Fermi-liquid (FL), BCS-like schemes and non-FL theories with electro-phonon or electronic mechanisms of pairing. The main difficulties are analysed in the light of some experimental observations paying special attention to those in which pairs exist or are claimed to be observed above Tc.read more
Citations
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Electronic specific heat of YBa2Cu3O6+x from 1.8 to 300 K
TL;DR: In this article, the electronic specific heatγ(x, T) of YBa2Cu3O6+x was determined for 0.16≤x≤0.97 from 1.8 to 300 K.
Journal ArticleDOI
Monte Carlo simulations of two-dimensional charged bosons
TL;DR: In this article, the ground-state energy and momentum distribution of charged bosons in two dimensions are calculated using analytic interpolation formulas embodying known asymptotic behaviors. But the results for the ground state energy and the momentum distribution are summarized in analytic interpolations.
Journal ArticleDOI
Lattice and spin bipolarons in metal oxides and doped fullerenes
A. S. Alexandrov,N. F. Mott +1 more
TL;DR: In this paper, the authors extrapolate the BCS theory to the strong electron-phonon and (or) electron-spin fluctuation interaction and show that in the strong-coupling limit the ground state is a charged Bose liquid of lattice and spin bipolarons.
Journal ArticleDOI
Spectroscopic evidence of low-energy gaps persisting up to 120 K in surface-doped p -terphenyl crystals
Haoxiang Li,Xiaoqing Zhou,Stephen Parham,Thomas Nummy,Justin Griffith,Kyle Gordon,Eric L. Chronister,Daniel Dessau +7 more
TL;DR: Using high-resolution photoemission spectroscopy on in situ potassium surface-doped para-terphenyl crystals, a low energy spectral gap of 12 meV was uncovered in this paper.
References
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Journal ArticleDOI
Possible high Tc superconductivity in the Ba-La-Cu-O system
TL;DR: In this paper, Ba−La−Cu−O system, with the composition BaxLa5−xCu5O5(3−y) have been prepared in polycrystalline form, and samples with x=1 and 0.75,y>0, annealed below 900°C under reducing conditions, consist of three phases, one of them a perovskite-like mixed-valent copper compound.
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Theory of Superconductivity
TL;DR: In this article, a theory of superconductivity is presented, based on the fact that the interaction between electrons resulting from virtual exchange of phonons is attractive when the energy difference between the electrons states involved is less than the phonon energy, and it is favorable to form a superconducting phase when this attractive interaction dominates the repulsive screened Coulomb interaction.
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The resonating valence bond state in La2CuO4 and superconductivity
TL;DR: The oxide superconductors, particularly those recently discovered that are based on La2CuO4, have a set of peculiarities that suggest a common, unique mechanism: they tend in every case to occur near a metal-insulator transition into an odd-electron insulator with peculiar magnetic properties.
Journal ArticleDOI
Superconductivity at 18 K in potassium-doped C60
Arthur F. Hebard,Matthew J. Rosseinsky,Robert C. Haddon,D. W. Murphy,S. H. Glarum,Thomas Palstra,A. P. Ramirez,A. R. Kortan +7 more
TL;DR: In this paper, low-temperature studies of potassium-doped C60 both as films and bulk samples, and demonstrate that this material becomes superconducting is demonstrated by microwave, resistivity and Meissner-effect measurements.
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Studies of polaron motion: Part II. The “small” polaron
TL;DR: In this article, the authors considered the case in which the electronic-overlap term of the total Hamiltonian is a small perturbation, and showed that the probability of off-diagonal transitions goes up exponentially with increasing temperature.