Finite size effect on critical transition temperature of superconductive nanosolids

The original Cooper pairing theory is reformulated for electrons confined in a layer. This analysis is motivated by the quasi-two-dimensional character of the oxidic superconductors, in case of which the extension of the initial (3D) Cooper framework is practically impossible. By considering the electrons moving in a flat box, due to quantum size effect the properties of these oxidic superconductors can be explained in a natural way. In this short communication we will concentrate to the variation of the critical transition temperature due to the layer thickness and to the number of conduction (Cu-O) planes. The results are confirmed by the experiment. This being an evidence for the presence of the charge confinement effect in the oxidic superconductors.

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The Finite Size Effect on The Metal-Insulator Transition of VO2 Films Grown by MOCVD

MRS Proceedings ◽

10.1557/proc-237-417 ◽

1991 ◽

Vol 237 ◽

Author(s):

Hyung Kook Kim ◽

R. P. Chiarello ◽

Hoydoo You ◽

M. H. L. Chang ◽

T. J. Zhang ◽

...

Keyword(s):

Phase Transition ◽

Particle Size ◽

Transition Temperature ◽

Size Effect ◽

Thermal Hysteresis ◽

Finite Size ◽

Finite Size Effect ◽

Transition Width ◽

Metal Insulator ◽

Out Of Plane

ABSTRACTWe studied the finite size effect on the metal-insulator phase transition and the accompanying tetragonal to monoclinic structural phase transition of VO2 films grown by MOCVD. X-ray diffraction measurements and electrical conductivity measurements were done as a function of temperature for VO2 films with out-of plane particle size ranging from 60–310Å. Each VO2 film was grown on a thin TiO2 buffer layer, which in turn was grown by MOCVD on a polished sapphire (1120) substrate. The transition was found to be first order. As the out-of plane particle size becomes larger, the transition temperature shifts and the transition width narrows. For the 60Å film the transition was observed at ∼61°C with a transition width of ∼10°C, while for the 310Å film the transition temperature was ∼59°C and the transition width ∼2°C. We also observed thermal hysteresis for each film, which became smaller with increasing particle size.

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Size Effect on Glass Transition Temperature of Nanopolymers

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.121-123.1317 ◽

2007 ◽

Vol 121-123 ◽

pp. 1317-1320 ◽

Cited By ~ 2

Author(s):

X.Y. Lang ◽

Qing Jiang

Keyword(s):

Glass Transition ◽

Transition Temperature ◽

Glass Transition Temperature ◽

Size Effect ◽

Methyl Methacrylate ◽

Finite Size ◽

Unified Model ◽

Finite Size Effect ◽

Interface Conditions ◽

Poly Methyl Methacrylate

A unified model is developed for the finite size effect on the glass transition temperature of polymers Tg(D) where D denotes diameter of particles or thickness of films. In terms of this model, Tg(D) depends on both the size and interface conditions. The predicated results are consistent with the experimental evidences of polystyrene (PS) and poly (methyl methacrylate) (PMMA) films and nanoparticles with different interface situations.

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Theoretical Investigation of the Size Effect on the Oxygen Adsorption Energy of Coinage Metal Nanoparticles

Catalysis Letters ◽

10.1007/s10562-021-03567-y ◽

2021 ◽

Author(s):

Amir H. Hakimioun ◽

Elisabeth M. Dietze ◽

Bart D. Vandegehuchte ◽

Daniel Curulla-Ferre ◽

Lennart Joos ◽

...

Keyword(s):

Particle Size ◽

Size Effect ◽

Adsorption Energy ◽

Single Point ◽

Finite Size ◽

Geometry Optimization ◽

Oxygen Adsorption ◽

Finite Size Effect ◽

Full Geometry Optimization ◽

Coinage Metal

AbstractThis study evaluates the finite size effect on the oxygen adsorption energy of coinage metal (Cu, Ag and Au) cuboctahedral nanoparticles in the size range of 13 to 1415 atoms (0.7–3.5 nm in diameter). Trends in particle size effects are well described with single point calculations, in which the metal atoms are frozen in their bulk position and the oxygen atom is added in a location determined from periodic surface calculations. This is shown explicitly for Cu nanoparticles, for which full geometry optimization only leads to a constant offset between relaxed and unrelaxed adsorption energies that is independent of particle size. With increasing cluster size, the adsorption energy converges systematically to the limit of the (211) extended surface. The 55-atomic cluster is an outlier for all of the coinage metals and all three materials show similar behavior with respect to particle size. Graphic Abstract

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