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Superconductivity

Prof. Dr. Markus Braden

2 h lectures (Monday, 10.00-11.30, Seminar room 201, II. Physikalisches Institut)

Start: Monday, October 17, 2016

 

The phenomenon of high-temperature superconductivity in the cuprates is one of the most fascinating problems in modern condensed matter physics, as even after ~30 years of intense research there is no consensus about the mechanism of this high-temperature superconductivity. In contrast the very recent observation of even higher superconducting transition temperatures in H3S at a very high pressure of several Mbar has been understood within a few months. Conventional electron phonon coupling even quantitatively explains these record superconducting transition temperatures approaching 200 K without the need for any adjustable parameter. The mystery about the cuprates superconductivity has recently been joined by the large family of iron-based superconductors, where again magnetism and superconductivity are closely interwoven, and where the mechanism is most likely unconventional. There obviously is a huge application potential for superconductors in particular in the fabrication of high field magnets. However, the use of superconductor in our daily life remains rather limited, which results from non-ideal properties of high-temperature superconductors and not only the still low transition temperatures.

This course gives an introduction to the basic concepts to understand superconductivity phenomenologically and microscopically. The Bardeen-Cooper-Schrieffer (BCS) theory to explain the pairing through the couling with phonons is mile stone in solid-state theory and can be applied to various other problems. Special efforts will be placed to introduce the families of high- or low-temperature superconductors, that attract most research activities today, i.e. the cuprates, the Fe-based materials and other unconventional superconductors.

 

 

Single crystals of superconducting Sr2RuO4 for inelastic neutron scattering experiments.

Lecture Notes

Literature

  • W. Buckel, R. Kleiner: Supraleitung
  • J. F. Annett: Superconductivity, Superfluids and Condensates
  • M. Tinkham: Introduction to Superconductivity
  • J.R. Waldram: Superconductivity of Metals and Cuprates
  • R. Gross, M. Marx: Festkörperphysik (Chapter 13)
  • D.R. Tilley, J. Tilley: Superfluidity and Superconductivity
  • K. Kopitzki: Festkörperphysik (Chap. 6)
  • K.H. Bennemann, J.B. Ketterson: Superconductivity Vol.1 & 2