Extremely strong coupling superconductivity in artificial twodimensional kondo. Strongcoupling theory of the interlayer tunnelling model for hightemperature superconductors. We argue that the extension of the bcs theory to the strongcoupling regime describes the hightemperature superconductivity of cuprates and the colossal magnetoresistance cmr of ferromagnetic oxides if the phonon dressing of carriers and strong attractive correlations are taken into account. However, despite being over a quarter of a century since its dis. Identifying and understanding the microscopic origin of hightemperature superconductivity stands as one of the greatest theoretical challenges of this century. We argue that the extension of the bcs theory to the strongcoupling regime describes the hightemperature superconductivity of cuprates and the colossal magnetoresistance cmr of ferromagnetic oxides if the phonon dressing of carriers and. Shallow pockets and very strong coupling superconductivity. The superconducting transition temperature is calculated as a function of the electronphonon and electronelectron coupling constants within the framework of the strongcoupling theory.
Order parameters of the system related to green functions of fermions are explicitly evaluated in the strong coupling limit. Brief introduction to superconductivity pdf 69p covered topics are discovery and first insights, the physics of the cooper pairs, bcs theory of superconductivity, characteristics of the superconducting state, the strong coupling theory, hightc superconducting materials, crystal structures, superconducting properties, models on the mechanism. Extremely strong coupling superconductivity of heavy. Based on the method of the equations of motion for twotime greens functions, we derive the dyson equation with the selfenergy operator in the form of the multiparticle greens function taking the interaction of electrons with phonons and spin. Flux quantization experiments indicate that the carriers, cooper pairs pairons, in the supercurrent have charge magnitude 2e, and that they move independently. Spin fluctuations and high temperature superconductivity. A textbook level presentation with formulation of a general theory of strongcoupling superconductivity will help students and researches to consolidate their knowledge of this remarkable class of materials. The mcmillanhopfield parameter is calculated in each case, in addition to the bergmann and rainer enhancement frequency. A unitary transformation is explicitly constructed by which the large interaction term of the hubbard model is exactly diagonalized. Strong coupling hubbard model and superconductivity. Download book strongcoupling theory of hightemperature superconductivity author. The bcs theory was successful to explain physical properties of these superconductors. A new mcmillan formula is assembled for the high temperature superconductors that evidences strong coupling in these materials. We consider a microscopic theory of the strong coupling in multiband superconductors with an arbitrary electronboson interaction.
Calculations using first principles methods and strong coupling theory are carried out to understand the electronic structure and superconductivity in cubic and tetragonal tih2. Superconductivity and bcs theory introduction electronphonon interaction, cooper pairs bcs wave function, energy gap and quasiparticle states predictions of the bcs theory limits of the bcs gap equation. Summary 7 bibliography 8 4 microwave electrodynamics of high temperature superconductors d. It is written on the occasion of the twentieth anniversary of the discovery of hightemperature superconductivity. Pseudogap and hightemperature superconductivity from weak to strong coupling. Hightemperature superconductors hts the cuprates, doped bismuthates. The general theory of strong coupling in cuprate superconductors strong coulomb correlations taken into account in the twoband hubbard model was formulated in 9, 10, and the twoband strongcoupling theory for describing superconductivity in mgb was considered in 11. Race to zero minds are like parachutes they only function when they are open james dewar, scottish physicist 1842 1923 liqui. Pdf the electronic properties of correlated metals with a strong. Within the bcs theory, the electronphonon interaction is the source of the attraction that binds two electrons into a paired state, generally referred to as cooper pairs. The cubic symmetry of the cuo layers and the lattice cohesion and oxygen presence are suggested reasons for the effect. The strongcoupling theory, in contrast, does not restrict.
Strong coupling theory of superconductivity northwestern university. We discuss several approaches, how they were benchmarked and how they agree sufficiently with each other that we can trust that the results are. The longrange froehlich electronphonon interaction has been identified as the most. Rubber, quarks and high temperature superconductivity.
However, to study both the mott transition and dwave superconductivity, one must resort to cluster versions of dynamical mean. Strongcoupling theory of hightemperature superconductivity. This superconductivity must be accompanied by a special type of magnetic order. Alexandrovrecent citations common fermiliquid origin of t2 resistivity and superconductivity in. The problem of hightemperature superconductivity is one of the most outstanding puzzles in contemporary physics. Electronphonon coupling and high temperature superconductivity 5 3. Extremely strong coupling superconductivity of heavyelectrons in twodimensions. The observation of hightemperature superconductivity in complex layered cuprates by bednorz and muller must now rate as one of the greatest experimental. Hightemperature superconductivity has transformed the landscape of solid state science, leading to the discovery of new classes of materials, states of matter, and concepts. The frequency is scaled in units of twice the zerotemperature gap, 2. Theory of high temperature superconductivity springerlink. The first hight c superconductor was discovered in 1986 by ibm researchers georg bednorz and k.
Strong coupling superconductivity, pseudogap, and mott. Fermiliquid theory of superconductivity to metals with strong electronphonon. Electronic structure and electronphonon coupling in tih 2. Strongcoupling theory of hightemperature superconductivity and colossal magnetoresistance article in proceedings of spie the international society for optical engineering 5932 july 2005.
Fluctuation conductivity in strongcoupling superconductors jetp. Hightemperature cuprate superconductors experiment. Pseudogap and hightemperature sup erconductivit y from w eak to strong coupling. Mechanism of hightemperature superconductivity in correlatedelectron systems.
This proposal was soon established definitively by a variety of. We examine the lowtemperature states supported by the quasiperiodic hostguest structure of elemental bismuth at high pressure, biiii. Strongcoupling theory of hightemperature superconductivity hightemperature superconductivity has transformed the landscape of solid state science, leading to the discovery of new classes of materials, states of matter, and concepts. Materials and mechanisms of superconductivity high temperature superconductors vi 2025 february 2000 houston, texas, usa kamel salama, weikan chu, paul c. Pdf pseudogap and hightemperature superconductivity. Strongcoupling theory of high temperature superconductivity. Pdf strong coupling theory of superconductivity researchgate. Strong coupling superconductivity in a quasiperiodic host. Click download or read online button to get new theory of superconductivity book now.
Pseudogap and hightemperature superconductivity from weak. An analysis of strong coupling in the high tc superconductors. In strongcoupling superconductors the transition temperature tc is compa. Pairing and superconductivity from weak to strong coupling. Free superconductivity books download ebooks online.
Hightemperature superconductivity hts of cuprates represents a challenge to the conventional theory. Theory of hightemperature superconductivity and effective. Strongcoupling theory of hightemperature superconductivity and colossal magnetoresistance strongcoupling theory of hightemperature superconductivity and colossal magnetoresistance alexandrov, a. New theory of superconductivity download ebook pdf, epub. It is a challenging research subject to clarify the mechanism of high temperature superconductivity, and indeed it has been studied intensively for more than 30 years. Pseudogap and hightemperature superconductivity from. Strongcoupling theory of the interlayer tunnelling model for high. The recentand verysurprisingbreakthroughsin phononmediated superconductivity can be put to use to provide a plausible recipe for the design of a room temperature superconductor. Our electronic transport and magnetization experiments establish biiii as a rare example of type ii superconductivity in an element, with a record upper critical field of 2. Strongcoupling theory for multiband superconductors. Physics and nanoengineering, edited by ivan bozovic, davor pavuna, proceedings of spie vol. Strongcoupling superconductivity beyond bcs and the key. It concludes with a discussion on models for exotic and high temperature superconductivity.
These lectures describe an approach, based on the extension of the bcs theory to the strongcoupling regime with small polarons and bipolarons. We argue that the extension of the bcs theory to the strongcoupling regime describes the hightemperature superconductivity of cuprates and the colossal. In the strongcoupling theory based on the green function formulation 76,77, the. From weak to strong coupling leads the reader from basic principles through detailed derivations and a description of the many interesting phenomena in conventional and hightemperature superconductors. Pdf strongcoupling description of the hightemperature.