MM-WAVE ABSORPTION AND RAMAN-SCATTERING FROM GLASS-LIKE FEATURES IN FLUORITE MIXED-CRYSTALS

One way to obtain new information about the ubiquitous low-lying two-l evel systems found in glasses is to identify them in appropriately mod ified crystals and then vary the crystal properties. Here our low-temp erature mm-wave absorption and Raman scattering measurements on a numb er of mixed fluorite crystals are reviewed. It is shown that these sin gle-crystal materials possess a broad distribution of two-level system s similar to what is found in the amorphous state. (C) 1998 Elsevier S cience B.V. All rights reserved.