BOND RELAXATION PHENOMENON AND IMPURITY MODES FREQUENCIES IN III-V-COMPOUNDS

In regard with recent studies which evidence the bond relaxation phenomenon in III-V solid solutions, a new approach is proposed to determine theoretically the isoelectronic impurity modes frequencies. It is based on an embedded molecular unit model which accounts for the relaxation in the neighborhood of the substituted atom and so avoids both the single-site and virtual crystal approximations. The results obtained for GaAs in some III-V compounds are compared with experimental data.