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. Superconductivity is characterized by a vanishing static electrical resistivity and an expulsion of the magnetic. Spb lack potential to answer several key questions as found with bcs theory of superconductivity and similar theories of high temperature superconductivity. As we have seen, phonons mediate an attraction between electrons. New theory of superconductivity download ebook pdf, epub. The main point of the bcs theory is that the attractive electronelectron interaction mediated by the phonons gives rise to cooper pairs, i. In this macroscopic quantum state, the electrons form. Scrrzrzzzzzf departmelt of physics, urtiversity of illinois, urbarta, itlirtois received july 8, 1957 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. John bardeen and the bcs theory of superconductivity volume 24 issue 1 lillian hoddeson. Cooper pairs and the bcs theory of superconductivity. The energy gap is related to the coherence length for the superconductor, one of the two characteristic lengths associated with superconductivity. Their theory in nonmathematical terms can be summarized as follows. Bcs theory or bardeencooperschrieffer theory is the first microscopic theory of superconductivity since heike kamerlingh onness 1911 discovery. 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.
The bcs theory of superconductivity developed in 1957 by bardeen, cooper and schrieffer has been remarkably successful in explaining the properties of superconductors. A successful theory of superconductivity was developed in the 1950s by john bardeen, leon cooper, and j. Theory of superconductivity university of illinois. Bcs theory of superconductivity the properties of type i superconductors were modeled successfully by the efforts of john bardeen, leon cooper, and robert schrieffer in what is commonly called the bcs theory. London and london derived a phenomenological theory of su perconductivity. Bcs theory, in physics, a comprehensive theory developed in 1957 by the american physicists john bardeen, leon n. Superconductivity is one of the most fascinating chapters of modern physics. More detailed accounts can be found in the excellent text books by. Pdf lecture note on superconductivity, solid state physics. Lecture notes on superconductivity a work in progress daniel arovas congjun wu department of physics university of california, san diego. Phenomenological theories of superconductivity figure 1. First, we reformulate the bcsbogoliubov theory of superconductivity from the viewpoint of linear algebra. The quantumfield approach to superconductivity theory. Beginning with the gap equation, we give the wellknown expression.
Click download or read online button to get on the theory of superconductivity book now. The effective net attraction between the normally repulsive electrons produces a pair binding energy on the order of millielectron volts, enough to keep them paired at extremely low temperatures. Find materials for this course in the pages linked along the left. The bcs theory was very successful in predicting the critical temperature of a material and provided an explanation for the isotope effect, according to which the critical temperature shifts as a function of the isotopic mass of chemical elements. Cooper pair and the bcs theory superconductivity and superfluid are very similar no resistivity vs no viscosity, which implies that the fundamental physics may be similar. This theory states that the electron experience special kind of attraction interaction, overcoming the coulomb forces off repulsion between them, as a result cooper pairs. The central feature of the bcs theory is that two electrons in the superconductor are able to form a bound pair called a cooper pair if they somehow experience an attractive interaction between. A microscopic theory of superconductivity was developed in 1957 by john bardeen, leon cooper and j. Translationalinvariant bipolarons and superconductivity.
Bcs theory of superconductivity hyperphysics concepts. Thesecooperpairsformthenacoherentmacroscopicgroundstate,whichdisplaysagapped spectrumandperfectdiamagnetism. The bcs theory gives a complete explanation of the nuclear relaxation time in a superconductor. In 1957 three american physicists john bardeen, leon cooper, and robert schrieffer advanced their theory superconductivity. Lecture note on superconductivity, solid state physics. But electrons are fermions, and we cannot have more than 1 electron on quantum state, so there is. Free superconductivity books download ebooks online. The remaining four chapters are devoted to the simplest phenomenological weak coupling theory of superconductivity on a microscopic level, the bcs theory, which provided the. Thus, superconductivity is often referred to as a macroscopic quantum phenomenon. Superconductivity and the bcs bogoliubov theory shujiwatanabe divisionofmathematicalsciences graduateschooolofengineering,gunmauniversity 42aramakimachi,maebashi3718510,japan email. We will discuss these basic experiments in the following chapter, but mainly this course is dealing with the theory of superconductivity. As a result, the theory developed and its analytical continuationeliashberg theory distort the reality and, in particular, make it impossible to construct a theory on the basis of the bec. A theory of superconductivity is presented, based on the fact that the interaction between electrons resulting from virtual exchange of phonons isattractive when.
Schrieffer their surname initials providing the designation bcs to explain the behaviour of superconducting materials. For this work, the authors were awarded the nobel prize in 1972. Lecture notes applied superconductivity electrical. Bcs theory \bcsbardeencooperschrie ertheoryisessentiallyjusthartreefocktheorylec. Robert schrieffer, for which they received the nobel prize in 1972.
John bardeen and the bcs theory of superconductivity. For the spin singlet state and swave symmetry a subsititon of the trial wave function in schrodinger equation 2, 1 2 e. Introduction superconductivity discovered in 1911 by onnes 9, is the quantum phenomena that certain materials exhibit under particular magnetic and temperature regimes. There is an energy barrier for the flux to go through the superconductor to escape time for. We will then calculate and study interesting quantities of the su. Mgb2, alkali under pressure, cac6 kohn anomaly, fermi surface nesting, twogap superconductivity. Lecture 23 superconductivity ii theory 4 physics 460 f 2000 lect 23 19 persistent currents how can the current stop flowing. Cooper problem ii 3 orbital part of the wave function spin singlet. A key conceptual element in this theory is the pairing of electrons close to the fermi level into cooper pairs through interaction with the crystal lattice. From this site you can access mp4 video files of all of the presentations given at the 50th anniversary of the bardeencooperschrieffer theory of superconductivity conference held in urbana, il on october 10, 2007. Superfluidity and becbcs crossover in an ultracold gas of fermionic atoms abstract ultracold quantum degenerate fermi gases provide a remarkable opportunity to study strongly interacting fermions. The complete microscopic theory of superconductivity was finally proposed in 1957 by bardeen, cooper and schrieffer.
This theory was developed by bardeen, cooper and schrieffer. The bcs theory predicts a bandgap of where t c is the critical temperature for the superconductor. Lecture notes on superconductivity a work in progress. This pair condensation is the basis for the bcs theory of superconductivity. Introduction in these lectures i want to give an introduction into the physical principles of superconductivity and its fascinating properties. Notes on the ginzburglandau theory icmr summer school on novel superconductors university of california, santa barbara. Click download or read online button to get new theory of superconductivity book now. Known universally as the bcs theory, this work, in addition to explaining the phenomena of superconductivity, has had profound implications for nearly every field of physics. The solid curve is the prediction from bcs theory, derived in chapter 3 below. Superconductivity an overview sciencedirect topics.
Robert schrieffer, which is known as the bcs theory. A guide to computational methods in superconductivity theory by s devaraj sahu, andreas langner and thomas f. We will look at features of superconductors before the discovery of the bcs theory, and examine the assumptions and methods used to develop the theory. Pippard concluding remarks colgate conference on superconductivity 1963 the dominant impression has been the overwhelming success of the bcs theory not only in explaining what. We discuss selfadjointness and symmetry of the bcs hamiltonian as well as spontaneous symmetry breaking. First i really realized that a brilliant theory of bcs was born from such a nice campus. Superconductivity discovered in 1911 by onnes 9, is the quantum phenomena that certain materials exhibit. The contrasting behavior of nmr relaxation rate with ultrasound absorption is explained in a natural manner by the pair nature of bcs wave function, providing proof of this central concept of the bcs theory. In contrast to other fermi systems, these gases have low densities and their interactions can be precisely controlled over an enormous range. In this section, we will see how superconductivity emerges in an electron gas with attraction the theory. Cooper and schrieffer or bcs in 1957, provides the better quantum explanation of superconductivity and account very well for all the properties exhibited by the superconductors. We move on to the ginzburg landau model and see how superconductivity can be explained through thermodynamic parameters, this is a macroscopic model and bcs theory is a special case of it when we apply certain limits. In 1957, bardeen, cooper and schrieffer proposed 3 a quantum theory of superconductivity, known as the bcs theory, for which they received a nobel prize.
This bcs theory explained the superconducting current as a superfluid of cooper pairs, pairs of electrons interacting through the exchange of phonons. Bcs theory cannot explain superconductivity in these highly correlated metals. In addition, concepts from bcs have been incorporated into diverse fields of physics, from nuclear physics and dense quark matter to the current standard model. Bcs theory of superconductivity questions and answers. Bcs theory is complex, so we summarize it qualitatively below. Bcs theory cornell laboratory of atomic and solid state physics. Nuclear magnetic resonance discussed below and other experimental.
George prepared for publication in journal of chemical education departments of chemistry and physics state university of new york at buffalo buffalo, new york 14260 december 1989. There existed no consistent microscopic theory that described why superconductivity arose, from the time it was dis. The theory describes superconductivity as a microscopic effect caused by a. Here we will discuss a new ground state of the interacting electron gas. We want to understand superconductivity using methods. On the theory of superconductivity download ebook pdf.
235 1624 1008 722 1212 577 878 1550 6 988 1394 1051 537 770 278 266 384 1362 1369 1614 465 679 349 7 998 711 1039 1524 1159 374 960 519 152 1002 1478 1150 1003 1254 270 971