Phys 250.2: Tight Binding Theory of Solids

In the spring quarter of 1999, Physics 250.2 will be a course on tight binding theory: its foundation in the 2nd quantized language, the representation of the energy bands of crystalline solids ("Slater-Koster parametrization"), and the form of popular many-body models and the simple mean-field treatment of them. The focus will be on achieving a clear understanding of the band problem and its tight binding representation, and of the uses it is put to.

The course will be offered in the 1999 spring quarter on Monday, 9:00 - 10:30 AM and on Friday, 12:30 - 2:00 PM.

At right is an immodest example of a band structure, immodest because this is a very complex, but very unusual magnetic system. The salient part of its band structure can probably be represented well by a tight binding model, although this has not yet been done.

Structure of the primitive cell of CaV4O9, which constains 28 atoms. CaV4O9 is a magnetic insulator that settles into a spin gap phase at low temperature in which there is not magnet order, yet it is not spin-glass like. It is also called a quantum spin ilquid.

This is the rather complex band structure of the ferromagnetic (ordered, hence fictitious) phase of CaV4O9. This system provides an excellent example of both the considerable success of modern band theory, and or its current limitations.