Influence of Non-Stoichiometric Defects on Optical Properties in LiNbO3

✍ Scribed by I.V. Kityk; M. Makowska-Janusik; M.D. Fontana; M. Aillerie; F. Abdi

• Publisher: John Wiley and Sons
• Year: 2001
• Tongue: English
• Weight: 232 KB
• Volume: 36
• Category: Article
• ISSN: 0232-1300
• DOI: 10.1002/1521-4079(200107)36:6<577::aid-crat577>3.0.co;2-3

✦ Synopsis

We present a band structure approach with a molecular dynamics cluster optimization which accounts for the various structural modifications related to the non-stoichiometry of LiNbO 3 crystals. The variation of the optical properties with the deviation from the stoichiometric composition can be understood within this approach. Particular role of the electron-phonon contributions to the electrooptics coefficient is shown. Model calculations yield a large dependence of the electrooptis coefficient r 22 on the crystal composition, in agreement with the experimental data. The observed minimum of the r 22 coefficient versus the non-stoichiometry is interpreted as originated from the noncentrosymmetry in the electrostatic potential distribution around Nb-O 6 clusters.