No abstract

No abstract

Optical absorption in stoichiometric and reduced, semiconducting single crystals of SrTi0 3 has been measured in the region 0.4-5 ju at room temperature and 77°K. Reduced crystals show a rapid increase of absorption with increasing wavelength beyond 0.6 fx, characteristic of free-carrier absorption. The absorption is proportional to electron concentration and nearly independent of temperature. For wavelengths between 0.7 and 2.5 fx the absorption varies as X 2 -5 , suggesting that longitudinal-optical-mode scattering is the dominant electron scattering mechanism at these temperatures. The magnitude of the observed freecarrier absorption is in poor agreement with that predicted from weak-coupling polaron theory but does agree with optical constants determined from recent reflectivity measurements. The validity of a weakcoupling theory is questionable in SrTi0 3 , since the electron-longitudinal-optical-phonon coupling constant is greater than 3.

No abstract

No abstract