A tight-binding parametrization of the band structure, along with a mean-field treatment of the Hund, electron-electron, and electron-lattice couplings, is used to obtain the full optical conductivity tensor of (Formula presented) as a function of temperature. We predict striking changes with temperature in the functional form and magnitude of the optical absorption. Comparison of our results with existing data makes it possible to determine the electron-lattice and electron-electron couplings. The effective “Hubbard U” is found to be (Formula presented) eV, rather less than the full bandwidth (Formula presented) eV, putting the material in the weak-intermediate coupling regime.
|Original language||English (US)|
|Number of pages||15|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|State||Published - Jan 1 2000|
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics