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Superconductivity
Published in Elaine A. Moore, Lesley E. Smart, Solid State Chemistry, 2020
Elaine A. Moore, Lesley E. Smart
It is the scattering of conduction electrons by the phonons that produces electrical resistance at room temperature. Superconductors have high resistance above the critical temperature because of their strong electron–phonon interactions. At low temperatures, it is predominantly the scattering by lattice defects that gives electrical resistance. BCS theory predicts that under certain conditions, the attraction between two conduction electrons due to a succession of phonon interactions can slightly exceed the repulsion that they exert directly on one another due to the Coulomb interaction of their like charges. The two electrons are thus weakly bound together, forming the so-called Cooper pair. It is these Cooper pairs that are responsible for superconductivity.
Introduction to nanotechnology and microtechnology
Published in V.M. Polunin, A.M. Storozhenko, P.A. Ryaplolv, Mechanics of Liquid Nano-and Microdispersed Magnetic Media, 2017
V.M. Polunin, A.M. Storozhenko, P.A. Ryaplolv
The strict correlation of the pairs results in the situation in which the state of all pairs in the given superconductor is characterised by the same wave function Ψ = |Ψ|β'φ, where φ is the phase of the wave function of the Cooper pair.
C
Published in Splinter Robert, Illustrated Encyclopedia of Applied and Engineering Physics, 2017
[condensed matter, electronics, solid-state] Pair of free electrons (conducting electrons) in a crystalline solid that behave as they are linked together by means of a long-range interaction. The Cooper pair provides a credible explanation of certain aspects associated with the phenomenon of superconductivity. The first observation of superconductivity was in 1911 by the Dutch physicist Heike Kamerlingh Onnes (1853–1926). The Cooper pair electrons will migrate through the lattice structure totally free of being impeded by the crystalline structure itself, nor any impurities, providing the conditions for zero resistance.
Impact of Electron-Phonon Interaction on Thermal Transport: A Review
Published in Nanoscale and Microscale Thermophysical Engineering, 2021
Yujie Quan, Shengying Yue, Bolin Liao
In principle, any states in a solid can be accurately determined by solving the Schrödinger equation involving all interactions between electrons and atomic nuclei. However, this full quantum mechanical treatment is infeasible for most condensed matter systems due to the complicated forms of interactions and a large number of involved atomic and electronic coordinates. To simplify this problem, in 1927, Born and Oppenheimer proposed that the electrons and atomic nuclei can be treated as separate quantum mechanical systems [24], the so-called Born-Oppenheimer approximation (BOA), given the fact that electrons are much lighter than atomic nuclei and that they move rapidly enough to adjust instantaneously to the much slower vibrations of the nuclei. Under BOA, the interaction term originating from the electrostatic potential generated by ionic vibrations, whose quantum description is the phonons, is dropped from the electronic Schrödinger equation. Although BOA has achieved great success in giving a reliable estimate of the total electronic energy given any atomic configurations, the dropped term, known as the EPI, is responsible for a broad range of phenomena. For example, the electrical resistance in metals at high temperatures is mainly attributed to the scattering of electrons by phonons; the attractive interaction between two electrons that form a Cooper pair, which is the origin of superconductivity, is mediated by phonons. Besides, the coupling between two electrons on the Fermi surface connected by a nesting wave vector and a phonon with a matching momentum leads to an abrupt change in the screening of lattice vibrations, which is manifested in the distortion of phonon dispersions, known as the Kohn anomaly [25].
Pierre-Gilles de Gennes and physics of liquid crystals
Published in Liquid Crystals Reviews, 2018
De Gennes and Saint-James (practically simultaneously to A.F. Andreev) had described the phenomenon, which was further on called the Andreev–Saint-James reflection. This is a reflection of an electron falling from the normal metal at the superconductor surface. As a result, the electron is transformed into a hole, and the newly emerging Cooper pair is involved in the conductivity process in a superconductor.