Êtes-vous un étudiant de l'EPFL à la recherche d'un projet de semestre?
Travaillez avec nous sur des projets en science des données et en visualisation, et déployez votre projet sous forme d'application sur Graph Search.
Concept
Unconventional superconductor
Résumé
Unconventional superconductors are materials that display superconductivity which does not conform to conventional BCS theory or its extensions.
The superconducting properties of CeCu2Si2, a type of
heavy fermion material, were reported in 1979 by Frank Steglich. For a long time it was believed that CeCu2Si2 was a singlet d-wave superconductor, but since the mid 2010s, this notion has been strongly contested. In the early eighties, many more unconventional, heavy fermion superconductors were discovered, including UBe13, UPt3 and URu2Si2. In each of these materials, the anisotropic nature of the pairing was implicated by the power-law dependence of the nuclear magnetic resonance (NMR) relaxation rate and specific heat capacity on temperature. The presence of nodes in the superconducting gap of UPt3 was confirmed in 1986 from the polarization dependence of the ultrasound attenuation.
The first unconventional triplet superconductor, organic material (TMTSF)2PF6, was discovered by Denis Jerome, Klaus Bechgaard and coworkers in 1980. Experimental works by Paul Chaikin's and Michael Naughton's groups as well as theoretical analysis of their data by Andrei Lebed have firmly confirmed unconventional nature of superconducting pairing in (TMTSF)2X (X=PF6, ClO4, etc.) organic materials.
High-temperature singlet d-wave superconductivity was discovered by J.G. Bednorz and K.A. Müller in 1986, who also discovered that the lanthanum-based cuprate perovskite material LaBaCuO4 develops superconductivity at a critical temperature (Tc) of approximately 35 K (-238 degrees Celsius). This was well above the highest critical temperature known at the time (Tc = 23 K), and thus the new family of materials was called high-temperature superconductors. Bednorz and Müller received the Nobel prize in Physics for this discovery in 1987. Since then, many other high-temperature superconductors have been synthesized.
LSCO (La2−xSrxCuO4) was discovered the same year (1986).
Source officielle
À propos de ce résultat
Cette page est générée automatiquement et peut contenir des informations qui ne sont pas correctes, complètes, à jour ou pertinentes par rapport à votre recherche. Il en va de même pour toutes les autres pages de ce site. Veillez à vérifier les informations auprès des sources officielles de l'EPFL.
Cours associés (11)
PHYS-756: Lectures on twisted bilayer graphene
Twisted Bilayer Graphene (TBG) is a change of paradigm in condensed matter: with flat topologic bands, it provides a platform for unconventional superconductivity, correlated insulation, Plankian meta
PHYS-420: Solid state physics IV
Solid State Physics IV provides a materials and experimental technique oriented introduction to the electronic and magnetic
properties of strongly correlated electron systems. Established knowledge is
PHYS-726: Introduction to Frustrated Magnetism
To provide an introduction to all aspects of the rapidly evolving field of frustrated magnetism:
- New paradigms: spin liquids, spin ice, topological order, ...
- Basic models and methods
- Experi
Publications associées (384)
Large impact of phonon lineshapes on the superconductivity of solid hydrogen
Phonon anharmonicity plays a crucial role in determining the stability and vibrational properties of high-pressure hydrides. Furthermore, strong anharmonicity can render phonon quasiparticle picture obsolete questioning standard approaches for modeling sup ...
Nature Portfolio2024Personnes associées (69)
Unités associées (5)
Concepts associés (2)
Théorie BCS
La théorie BCS est une théorie de la supraconductivité qui fut proposée en 1957 par John Bardeen, Leon Neil Cooper, et John Robert Schrieffer. Elle explique la supraconductivité par la formation de paires d'électrons (paires de Cooper) sous l'effet d'une interaction attractive entre électrons résultant de l'échange de phonons. Pour leur travail, ces auteurs obtinrent le prix Nobel de physique en 1972. Il est possible de comprendre l'origine de l'attraction entre les électrons grâce à un argument qualitatif simple.
Supraconductivité
La supraconductivité, ou supraconduction, est un phénomène physique caractérisé par l'absence de résistance électrique et l'expulsion du champ magnétique — l'effet Meissner — à l'intérieur de certains matériaux dits supraconducteurs. La supraconductivité découverte historiquement en premier, et que l'on nomme communément supraconductivité conventionnelle, se manifeste à des températures très basses, proches du zéro absolu (). La supraconductivité permet notamment de transporter de l'électricité sans perte d'énergie.