PX385 Condensed Matter Physics

Weighting: 15 CATS

The quantum and statistical mechanics of electrons are the basis for describing the physics of condensed matter. The module studies the role of the microscopic structure in determining the properties of macroscopic samples. It explains a range of magnetic and conductivity phenomena, and how to measure these experimentally.

Aims:
To provide an understanding of phenomena in condensed matter, both from an experimental and theoretical perspective.

Objectives:
At the end of the module, you should:

• understand that quantum and statistical mechanics are the basis for describing the physics of solids, and be able to apply the ideas to problems in condensed matter
• understand the role of the microscopic structure in determining the properties of macroscopic samples
• be able to explain magnetic and conductivity phenomena, and how to measure these experimentally.

Syllabus:

1. How materials behave
Types of bonding (ionic, covalent etc.); the periodic table; one dimensional models of solids;
crystal structures, defects & disorder; thermal vibrations; how to measure crystal structure.

2. Free electrons
Free electron model; ground state, Fermi energy, transport properties; Wiedemann-Franz law;
Peltier effect; where this breaks down.

3. Band structure
Nearly free electron model: the effect of a periodic potential; Blochâ€™s theorem; scattering; band
gaps; metal, insulator or semiconductor; density of levels; tight binding model. Moving beyond
1D: Brillouin zones and Fermi surfaces; real metals; electrons in magnetic fields; how to measure
the Fermi surface, and it is important (de Haas van Alphen, cyclotron resonance, etc.)

4. Semiconductors in more detail
Effective mass; impurities in semiconductors; holes; designing band gaps; Hall effect; p-n
junctions; other applications, such as LEDs, lasers, solar cells.

5. Magnetism & magnetic order
Origins of magnetic behaviour; paramagnetism and magnetic resonance measurements;
diamagnetism; magnetic ordering such as ferromagnetism and antiferromagnetism;
Curie temperature; domains, hysteresis; applications - magnetic memory, refrigeration, single
molecule magnets & quantum computationâ€¦

6. Other Topics
Superconductivity; low dimensional systems (2DEG, quantum Hall effect, quasi-1D and 2D
systems); insulators; glasses.

Commitment: 30 Lectures

Assessment: 2 hour examination