Ab-initio spin-density pseudopotential calculation of the local vibrations of the oxygen complexes in silicon

✍ Scribed by M. Pesola; J. von Boehm; T. Mattila; R.M. Nieminen

• Book ID: 104109037
• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 42 KB
• Volume: 121-122
• Category: Article
• ISSN: 0010-4655
• DOI: 10.1016/s0010-4655(06)70119-9

✦ Synopsis

The local vibration modes (LVM) of the oxygen interstitial (Oi) and vacancy (V) oxygen complexes in silicon ,are studied using the ab-initio local spin-density pseudopotential method. All calculations ,are performed in a massively parallel CRAY-T3E system using the FINGER code. The Vanderbildt and Haman pseudopotentials are used for O and Si, respectively. A kinetic energy cut-off of 28 Ry, 32 atom site supercells and 23 Monkhorst-Pack k-points are used. The LVM for Oi, Oi2, VO and VO2 are calculated diagonalizing the dynamic matrix as well as for VO from the discrete Fourier transform of the velocity autocorrelation function obtained using molecular dynamics simulation. Both methods give practically the same LVM frequencies for VO. For VO and VO2 the calculated LVM agree closely with the experimental LVM reflecting, however, a slight overbinding. The calculated LVM frequencies for Oi and Oi2 differ more significantly (50-100 cm -1) from the experimental ones. However, the calculated LVM frequency differences are similar to the experimental ones (within 3 cm-1).