Temperature modulation and damping of an anharmonic two-phonon spectrum

✍ Scribed by J.M. Wesselinowa; I.J. Lalov

• Publisher: Elsevier Science
• Year: 1986
• Weight: 907 KB
• Volume: 141
• Category: Article
• ISSN: 0378-4363
• DOI: 10.1016/0378-4363(86)90253-6

✦ Synopsis

In the present paper a two-phonon spectrum in the frequency region of the sum or difference of the frequencies of two optical phonons is studied. A quartic anharmonicity is investigated as a factor for damping of the one-and two-phonon states as well as a mechanism binding two phonons into a biphonon. The numerical calculations of the dynamical structure factor give the complete picture of the two-phonon spectrum, e.g. the temperature modulation of the frequencies, width and the intensity of the spectral lines for different values of the anharmonicity and at various widths of the phonon bands. The possibility for a temperature modulation of the biphonon levels in the sum of frequencies region and for the existence of bound states in the region of the difference of the phonon frequencies is shown.