Electron paramagnetic resonance on iron-acceptor pairs in silicon

Experimental data obtained by electron paramagnetic resonance on silicon doped with aluminum and iron are presented. After quenching the sample and a short stay at room temperature, two spectra, labeled Si-NL27 and Si-NL28, were observed. It is concluded that the spectra originate from two Fe-A1 pairs with different symmetry. The spectra can be described with an effective spin J=1/2 and g factors significantly deviating from 2. A theoretical investigation of the g-value tensors of iron-acceptor pairs allows an interpretation of the g factors in terms of crystal-field splitting and spin-orbit coupling.