Electronic states of Mn4 complex cluster in silicon

Abstract

Recently, Kreissl and Gehlhoff have observed an EPR spectrum which was associated with the Mn4 complex cluster in Si. In order to account for the observed hyperfine lines a total spin S = 6 and an orbital singlet were ascribed to the complex. However, the same complex has been identified previously also by EPR in a pioneering work by Ludwig and collaborators, where a spin S = 2 was adopted to describe the observed hyperfine interactions. As an attempt to solve this controversy we have carried out, for the first time, SCF spin-polarized one-electron state calculations for the Mn4 complex in Si. The results were obtained by using a molecular cluster model and the multiple-scattering Xα theory. The calculations indicate that the reported interpretations of the EPR spectra ascribed to the Mn4 complex in silicon must be reviewed.