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PX446 Condensed Matter Physics II

Lecturers: Paul Goddard, James LLoyd-Hughes, Oleg Petrenko

Weighting: 15 CATS

Many phenomena observed in condensed matter, like magnetism and superconductivity, are the result of interactions between electrons. This module looks at some of these phenomena, how to observe them and how to use them.

An important concept in the modelling of these many-electron systems is Landau's idea of the quasiparticle. Excitations of a system of interacting particles can be put into one-to-one correspondence with excitations of non-interacting particles but with a finite lifetime. It's a brilliant idea and helps us understand many (almost all) measurable properties of interest. Landau also set up the most important models of the free energy of the magnets and superconductors in applied fields, which we will be studying.

Aims
To offer an account of important electronic properties of materials. Topics covered will be magnetism, electronic transport, optical properties of matter and superconductivity. There should be an emphasis on the connection between theory and experiment, and emerging ideas such as quantum criticality and topology may be discussed.

Objectives
Students will:

  • Understand aspects of some magnetic, electrical, optical and superconducting properties of materials;
  • Become aware of the existing range of functional materials and the experiments used to probe their properties;
  • Have developed insight into areas of research interest in condensed matter physics

Syllabus

1. Magnetism
Introduction (revision of topics covered by PX385 Condensed Matter Physics). Exchange interactions: ferromagnets; antiferromagnets; ferrimagnets and others. Symmetry and models, Landau theory, excitations. Experimental techniques in magnetism, contemporary magnetism.
2. Quasiparticles & Excitations
Bandstructure: tight-binding approach, quasiparticles. Experimental methods, semiconductor optics. Magnetism in semiconductors. Quasiparticles beyond the single particle picture.
3. Superconductivity
Basic properties of superconductors, electromagnetism of superconductors and the London equations, phase transitions and the Ginsburg-Landau theory. Phase coherence and the Josephson effects. Overview of BCS theory, experimental evidence for the energy gap. Unconventional superconductors. Superconducting technology

Commitment: 30 lectures

Assessment: 2 hour examination

The module has a website.

Recommended Texts:
Magnetism in condensed matter, Stephen Blundell, OUP 2001;
Optical properties of solids, Mark Fox,
OUP 2010;
Band theory and electronic properties of solids,
John Singleton, OUP 2011;
Superconductivity, superfluids, and condensates,
James F. Annett, OUP 2013;