With spectroscopic ellipsometry the optical properties of high quality YBa2Cu3O6 thin films deposited by off-axis magnetron sputtering were investigated in situ. The optical transition at 4 eV of these films that were not exposed to atmospheric condition shows a two times higher magnitude than reported previously and can be described by a single Lorentz oscillator in the complete temperature range of 20 °C–700 °C. The width of the Lorentz oscillator is remarkably small. Combined with the temperature-independent strength of one electron per unit cell of the 4-eV transition, it is an indication that this optical transition takes place between a quite isolated occupied and unoccupied level of the electronic structure.
|Number of pages||4|
|Journal||Physical review B: Condensed matter and materials physics|
|Publication status||Published - 1998|