On the formation of boron-germanium pairs in silicon-germanium mixed crystals

摘要

By the β-NMR technique using polarised ~(12)B nuclei, a cylindrical electric field gradient in boron was detected which is found to be the manifestation of a boron-germanium pair in silicon-germanium mixed crystals. The field gradient is aligned along the < 1 1 1 >-axis of the crystal and has a value of V_(zz) = +3.8(3) V/A~2. Calculations on the basis of a full-potential DFT program delivered values for local bond lengths and electronic charge distributions in impurity complexes and confirmed the above assignment. The probability of the formation of the complex matches with statistical expectations.