Saturday, August 29, 2009

Watching Mott and Hubbard kill quasi-particles

This morning I gave a seminar, "Destruction of quasi-particles near the Mott insulator transition" to the Condensed Matter Physics group at University of Toronto. A few points I tried to emphasize in the talk were:

The frequency dependent optical conductivity is a powerful probe of many-body effects in strongly correlated electron materials. In particular, for a wide range of materials one observes a significant redistribution of spectral weight, with only a small amount of weight in the Drude peak, which often only exists at temperatures much less than the energy scales associated with the band structure.

The absence of a Drude peak is associated with destruction of Fermi-liquid quasi-particles. Other signatures of a bad metal include a non-monotonic temperature dependence of the resistivity, thermopower, and Hall constant.

Dynamical mean-field theory gives a quantitative description of the redistribution of spectral weight in organic charge transfer salts near the Mott-Hubbard insulating phase.

The talk was largely based on this PRL, a combined theory and experiment work.

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