This same process is also obtained, moreover, as a result of the com bined action of h1, h2 thus, for example, in the second order in the coupling constant g, we have the diagrams shown in fig. Introduction to superconductivity differs from the first edition chiefly in chapter 11, which has been almost completely rewritten to give a more physicallybased picture of the effects arising from the longrange coherence of the electronwaves in superconductors and the. More detailed accounts can be found in the excellent text books by w. By focusing our attention on them we were able to construct a theory of superconductivity. Superconductivity is destroyed by either raising the temperature or by applying a magnetic eld. In this macroscopic quantum state, the electrons form. It was published in 1957, 46 years after the original discovery of the phenomenon by kamerlingh onnes2. The superconducting properties of small specimens 9. Superconductivity, complete disappearance of electrical resistance in various solids when they are cooled below a characteristic temperature. There existed no consistent microscopic theory that described why superconductivity arose, from the time it was dis. Tinkham, introduction to superconductivity 2nd editiondover, 2004. The average energy in the superconducting transition may be estimated from tc as 108 evatom. This theory is based on the idea that there is an attractive interaction between electrons caused by the phonons.
Lecture notes on superconductivity a work in progress. Nearly a century after its first discovery, its full commercial potential is. One is the history of superconductivity, and the other is what richard feynman had to do with it. We want to understand superconductivity using methods. The existing phenomenological theory of superconductivity is unsatisfactory, since it does not allow us to determine the surface tension at the boundary between the normal and the superconducting phases, and does not allow for the possibility to describe correctly the destruction of superconductivity by a magnetic field or current.
The problem of formulating a microscopic theory of superconductivity is also considered. In the first part, a general equation for the superconductivity is. The simple facts of superconductivity as of 1955 in 1911, kammerling onnes found that the resistance of a mercury sample disappeared suddenly below a critical temperature. The second approximation applies not only to the particle distribution pattern but also to the correlation function. The main point of the bcs theory is that the attractive electronelectron interaction mediated by the phonons gives rise to cooper pairs, i.
Superconductivity of a metal mainly depends on the temperature and strength of the magnetic field in which the metal is placed. More detailed accounts can be found in the excellent text books by. Superconductivity is characterized by a vanishing static electrical resistivity and an expulsion of the magnetic. Unlike an ordinary metallic conductor, whose resistance decreases gradually as its temperature is lowered even. Any material exhibiting these properties is a superconductor. We will discuss these basic experiments in the following chapter, but mainly this course is dealing with the theory of superconductivity. Timeline of superconductors and their transition temperatures from wikipedia. This temperature, called the transition temperature, varies for different materials but generally is below 20 k.
So far, the highest reproducible t c is 125 k, still far below room temperature, which is about 300 k. Richard feynman and the history of superconductivity david goodstein and judith goodstein this paper deals with two topics. Mechanism of superconductivity isotope effect, tc depends on the mass of atoms t c mass of atoms constitutingthe crystallattice. A general theory of superconductivity with points of view differing from those of the bcs theory is presented in two parts. 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. Yet the 1955 simple facts of superconductivity capture the great qualitative change that occurs in the transition to the superconducting state.
Superconductivity is the set of physical properties observed in certain materials, wherein electrical resistance vanishes and from which magnetic flux fields are expelled. New method in the theory of superconductivity 43 vacuum, gives the diagram of fig. The existing phenomenological theory of superconductivity is unsatisfactory, since it does not allow us to determine the surface tension at the boundary between the normal and the superconducting phases, and does not allow for the possibility to describe correctly the destruction of superconductivity by a. These lectures attempt at a concise description of what has been achieved so far in this direction for the understanding of the electronphonon mechanism of superconductivity. Origins of the theory of superconductivity leon n cooper university of illinois october 10, 2007. Theory of superconductivity advanced books classics.
Introduction superconductivity discovered in 1911 by onnes 9, is the quantum phenomena that certain materials exhibit under particular magnetic and temperature regimes. Chapter 1 contains theoretical discussions about the possibility of room temperature superconductivity. The microscopic theory of superconductivity was developed by bardeen, cooper and schrieffer bcs1. Introduction to the theory of superconductivity pdf 82p this note covers the following topics. Incidentally, the commonly known hubbard u was actually called i by hubbard, following john slaters notation used in a precursor to the model. The microscopic theory of superconductivity is an excellent example of a steady seventy years progress towards this goal which is still further going on. Superconductivity is widely regarded as one of the great scientific discoveries of the 20th century. The essential point is that below tc the binding energy of a pair of electrons causes the opening of a gap in the energy spectrum at e f the fermi energy the highest occupied level in a solid, separating the pair states. A theory of superconductivity is presented, based on the fact that the interaction between electrons resulting from virtual exchange of phonons isattractive when.
Richard feynman and the history of superconductivity. Superconductivity is a unique and powerful phenomenon of nature. The history of superconductivity can be traced back to michael faraday and the. This book contains detailed insights on the calculus of variations that studies the equilibrium density matrix for manyparticle fermi systems. On the theory of superconductivity the existing phenomenological theory of superconductivity is unsatisfactory since it does not allow us to determine the surface tension at the boundary between the normal and the superconducting phases and does not allow for the possibility to describe correctly the destruction of superconductivity by a magnetic field or current. The microscopic theory of superconductivity was developed by bardeen, cooper and. Macroscopic theory of superconductivity valid for magnetic fields of arbitrary magnitude and the behaviour of superconductors in weak high frequency fields are discussed. Abrikosov, fundamentals of the theory of metalsnorthholland, 1988. Eremin, maxplanck institut fur physik komplexer systeme, dresden, germany. 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. Hubbard found the model to be the simplest that produces both a metallic and an insulating state, depending on the value of u. Introduction to the theory of superconductivity cryocourse 2009 helsinki, finland n. The theory is also used in nuclear physics to describe the pairing.
Bcs theory or bardeencooperschrieffer theory named after john bardeen, leon cooper, and john robert schrieffer is the first microscopic theory of superconductivity since heike kamerlingh onness 1911 discovery. Is it correct to talk about the vanishingof the electrical resistance. Introduction in these lectures i want to give an introduction into the physical principles of superconductivity and its fascinating properties. On the theory of superconductivity in this paper it is shown that at average values of the magnetic field different from zero a superconductor must break up not into two regions, viz. Due to this interaction, the electrons form bound pairs. A series of films prepared by bartek glowacki to introduce undergraduate and postgraduate students to superconductivity and its applications, including interviews with leading experts from academia and industry. This theory might be a step toward new, highertemperature superconductors that would revolutionize electrical engineering with more efficient motors. While einstein s concept of molecular conduction chains did not turn out to be the right one, he was correct in insisting that a theory of superconductivity cannot be based on the concept of noninteracting electrons in solids. During those intervening years numerous scientists tried and failed to develop an understanding of superconductivity, among them the. He discovered that the resistivity of mercury absolutely disappears at temperatures below about. Yet meissner and ochsenfeld found that below tc the.
Superconductivity is the phenomenon of exactly zero electrical resistance. Unlike an ordinary metallic conductor, whose resistance decreases gradually as its temperature is lowered even down to near absolute zero, a superconductor has a. New superconductor theory may revolutionize electrical. Robert schrieffer, which is known as the bcs theory. Fernandes here we will discuss a new ground state of the interacting electron gas. Introduction to superconductivity differs from the first edition chiefly in chapter 11, which has been almost completely rewritten to give a more physicallybased picture of the effects arising from the longrange coherence of the electronwaves in superconductors and the operation of quantum interference devices. Here we will discuss a new ground state of the interacting electron gas. He discovered that the resistivity of mercury absolutely disappears at temperatures below. It was published in 1957, 46 years after the original. Its significance in causing superconductivity is confirmed by the dependence of the critical temperature of superconductors on the isotopic mass of the lattice, a. The theory describes superconductivity as a microscopic effect caused by a condensation of cooper pairs. Oct 25, 2007 macroscopic theory of superconductivity valid for magnetic fields of arbitrary magnitude and the behaviour of superconductors in weak high frequency fields are discussed. Good conductors weak scattering from the lattice are poor superconductors low tc. However, in the wake of the hightemperature superconductivity revolution, one particular adaptation of hubbards original model called the tj model originally arising in the context of doped motthubbard insulators emerged as a compelling candidate for hosting a superconducting state.
Phenomenological theories of superconductivity figure 1. Bogoliubov mathematics institute, academy of sciences, u. There are two approximations taken into account in the book. Thesecooperpairsformthenacoherentmacroscopicgroundstate,whichdisplaysagapped spectrumandperfectdiamagnetism. This superconducting state is called the bcs state and the hamiltonian they dealt with is called the bcs hamiltonian. A microscopic theory of superconductivity was developed in 1957 by john bardeen, leon cooper and j. Superconductivity in metals was the stage of another breakthrough in the 1980s with the discovery of high tc superconductors. Superconductivity basic phenomenon if a material is described as a superconductor, below a certain temperature the critical temperarure it loses its electrical resistivity to become a perfect conductor. In the chapters 2, 3, 4 and 5 are discussed interesting. Schrieffer,theory of superconductivityperseus books, 1999 t. 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. Background history kammerlingh onnes liquefying of he in 1908. 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. We will then calculate and study interesting quantities of the su.