SUPERCONDUCTIVITY AND LOW TEMPERATURE PHYSICS

Chalmers University of Technology, MC2

Per Delsing, Dag Winkler, November 2006

 

A.        SUPERCONDUCTIVITY

Introduction                                History, Electric, magnetic, and thermal properties, critical temperatures

Thermodynamic treatment         Thermodynamics of superconductors, two-fluid model

Electromagnetic response           Perfect conductivity, London theory, quantized flux, coherence

Superconductors in magn field   Demagn coeff, intermediate state, surface energy, Type I & II

Ginzburg-Landau Theory          Basic eqs, characteristic lengths, Abrikosov model, H_c2, flux lattice, fluctuations
Microscopic Theory                  Clues, strategy, Cooper pairs, attractive potential between charge carriers, BCS theory, main assumptions and results, energy gag

High T_c Superconductivity       Discovery, compounds, structure, properties, instabilities, models, prospects and problems

 

References:

J R Waldram: Superconductivity of metals and cuprates, Institute of Physics, Bristol, 1996 pbk

Supraledning: Föreläsningsanteckningar av T Claeson, 1984.High Tc-Superconductivity, T. Claeson, 1997.

J.R. Schrieffer: Theory of Superconductivity, W.A. Benjamin, 1964

M. Tinkham: Introduction to Superconductivity, McGraw-Hill, N.Y. 2^nd ed.

V.V. Schmidt, The physics of superconductors: Introduction to fundamentals and applications, Springer, Berlin, 1997

 

B.        SUPERCONDUCTING TUNNELING and DEVICES

Tunnel Phenomena                  Superconducting tunneling, energy gap, density of excited states, photon and phonon assisted tunneling, strong coupling

Josephson effect                      Ac and dc Josephson effects, Josephson junctions, RSJ model, Josephson inductance

Proximity effect                       Interfaces between superconductors and normal metals, Andreev reflection
Devices                                   Short overview of superconducting Devices such as SQUIDs and Single electron transistors

References:

J R Waldram: Superconductivity of metals and cuprates, Institute of Physics, Bristol, 1996 pbk
T. van Duzer and C.W. Turner: Principles of Superconductive Devices and Circuits, Elsevier, N.Y. 1981

L. Solymar: Superconductive tunneling and applications

 

C.        LOW TEMPERATURE TECHNIQUES, CRYOGENICS

Introduction                                    Definitions, history, importance

Cooling methods                            Principles, reversible and irreversible processes, examples, heat exchangers, practical liquifiers, mechanical coolers, cryoliquids

Cooling methods for T<1 K           ³He, adiabatic demagnetization of paramagnetic salts and nuclear spins, dilution refrigerator, Pomeranchuk refrigerator

Thermal isolation and contact         Conduction via gas, solid, radiation, other causes, heat switches, practical designs

Thermometry                                  Temperature, temperature scales, fix and calibration points, primary and secondary thermometers, gas thermometer,
        resistance thermometers, thermocouples, magnetic thermometers, nuclear orientation, noise, ³He, transition temps

 

References:

G.K. White and P.J. Meeson: Experimental Techniques in Low Temperature Physics, Oxford Univ. Press, 2002

F. Pobell: Matter and methods at low temperature, Springer

A. Kent: Experimental Low Temperature Physics, MacMillan Press, 1993

O.V. Lounasmaa: Experimental Principles and Methods Below 1 K, Acad.Press, 1977

 

D.        LIQUID AND SUPERFLUID HELIUM

Introduction:                            Review, History

Basic properties of ⁴He:          Permanent liquid, phase diagram, properties, phase transitions

Two fluid model:                    Bose-Einstein condensation, normal and superfluid densities, viscosity, thermo-mechanical effects, heat propagation,
second sound, momentum of heat flow

Excitations of superfluids:      Phonons, rotons, dispersion relations, normal fluid density, superfluidity, critical velocity, absorption of sound

Helium in rotation:                 Classical liquid contra superfluid, experiments on rotation, vortices, critical velocities

³He as a Fermi liquid

³He/⁴He mixtures                   Dilution regfrigeration

Superfluidity in ³He:              Phenomenon, phase diagram, models, symmetry, properties

 

References:

D.R. Tilley and J. Tilley: Superfluidity and Superconductivity, 3rd ed. (Institute of Physics, Publ., Bristol, 1996

J. Wilks: An Introduction to Liquid Helium, Clarendon, Oxford 1970

Physics Today, Febr. 1987, special issue on ³He and ⁴He