Theory of superconductivity

I lO] Anderson P W 1997 The Theory of Superconductivity in the High-Ti Cuprates (Princeton Series in Physics) (Prinoeton Prinoeton University Press)... 

Hamiltonians equivalent to (1) have been used by many authors for the consideration of a wide variety of problems which relate to the interaction of electrons or excitons with the locaJ environment in solids [22-25]. The model with a Hamiltonian containing the terms describing the interaction between excitons or electrons also allows for the use of NDCPA. For example, the Hamiltonian (1) in which the electron-electron interaction terms axe taken into account becomes equivalent to the Hamiltonians (for instance, of Holstein type) of some theories of superconductivity [26-28]. 

J. Bardeen (Urbana), L. N, Cooper (Providence) and J, R. SchriefFer (Philadelphia) theory of superconductivity, usually called the BCS theory. 

THE RESONA TING-VALENCE-BOND THEORY OF SUPERCONDUCTIVITY CREST SUPERCONDUCTORS AND TROUGH SUPERCONDUCTORS ... 

The theory of superconductivity based on the interaction of electrons and phonons was developed about thirty years ago. I 4 In this theory the electron-phonon interaction causes a clustering of electrons in momentum space such that the electrons move in phase with a phonon when the energy of this interaction is greater than the phonon energy hm. The theory is satisfactory in most respects. 

Ginzburg Landau theory of superconductivity Beyond the post Gaussian approximation... 

The properties of the asymmetric superconductors have been an exciting subject since the advent of the BCS theory of superconductivity more than four decades ago. While the early studies were motivated by the effects of the para-... 

The Mechanism of Superconductivity. A satisfactory theory of superconductivity was proposed in 1957 by the American physicists John... 

The classical tunneling experiment of Giaever (1960) provided unambiguous proof of the BCS theory of superconductivity. The STM as a local tunneling probe is certainly suitable to probe the local properties of superconductors, such as the local structure of the Abrikosov flux lattice. The work of Hess and co-workers (1989, 1990, 1990a, 1991) is a prominent example. 

Another type of polarizibility results from the near degeneracy of the metal levels and the oxygen 2p levels. This is directly related to the high covalency in these systems thus, this type of polarizibility will be greater for the higher oxidation states of copper and bismuth. Both of these polarizibility contributions are likely very important for theories of superconductivity based on charge fluctuations. 

In 1957, Bardeen, Cooper, and Schrieffer published their theory of superconductivity, known as the BCS theory. It 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 a so-called Cooper pair. It is these Cooper pairs that are responsible for superconductivity. In conventional superconductors, these electrons are paired so that their spin and orbital angular momenta cancel. They are described by a wave function, known as an order parameter. In this case the order parameter has symmetry similar to that of the wave function of s electrons and represents a singlet state. 

Challenges to Established Theories, It is interesting to note that some theoreticians struggle with describing how superconductivity occurs at high temperatures in the newer, ceramic superconductors. This is understandable because the classic theory of superconductivity is tied to metals. Most ceranuc superconductors discovered to date incorporate distinctive layers of copper and oxygen atoms, One question posed by some researchers, Is the mechanism of high-temperature superconductivity the same in hole superconductors as it is in electron superconductors ... 

Schrieffer. J.R. The Theory of Superconductivity, Perseus Publishing, Boulder, CO, 1999. 

In 1957, Bardeen, Cooper and Schriffer proposed a microscopic theory of superconductivity [2], This theory was isotropic (s-wave pairing). In 1958, Bogoliubov [3] and Valatin [4] introduced a transformation that made the treatment of superconductivity simpler (quasi-particle transformation). Still in 1958, Anderson [5] addressed the same problem by introducing the algebra of SU(2) to describe the properties of the system (quasi-spin algebra). In the same year, Bohr, Mottelson and Pines applied BCS theory to... 

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