Evidence of N substitution by Mn in GaN

Abstract

We report on the lattice location of Mn in wurtzite GaN using ${\ensuremath{\beta}}^{\ensuremath{-}}$ emission channeling. In addition to the majority substituting for Ga, we locate up to 20$%$ of the Mn atoms in N sites. We propose that the incorporation of Mn in N sites is enabled under sufficiently high concentrations of N vacancies, and stabilized by a highly charged state of the Mn cations. Since N substitution by Mn impurities in wurtzite GaN has never been observed experimentally or even considered theoretically before, it challenges the current paradigm of transition metal incorporation in wide-gap dilute magnetic semiconductors.