Dielectric and light scattering spectroscopy of incommensurate phases in crystals

1 January 1981

journal article
research article
Published by Taylor & Francis in Phase Transitions

Vol. 2 (3) , 155-229
https://doi.org/10.1080/01411598108241319

Abstract

Dielectric and light scattering spectroscopy are the most sensitive methods for the direct observation of low-frequency excitations in incommensurate phases. In several cases they have been successfully used for the observation of amplitudon and phason modqs. Whereas the amplitudon below the normal-incommensurate transition temperature behaves in a similar way to soft modes at common structural transitions, the phason represents a qualitatively new feature of incommensurate phases. All the corresponding experimental data published up to the middle of 1980 are reviewed and consistently interpreted taking into account the specific selection rules recenily derived. The necessary theoretical background is discussed qualitatively.

Keywords

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