Core-level photoemission study ofGa1−xMnxAs

Abstract

We have studied the electronic structure of Mn impurities in GaAs by Mn $2p$ core-level photoemission spectroscopy. From cluster-model analysis assuming the neutral $\left({\mathrm{Mn}}^{3+}\right)$ or negatively ionized $\left({\mathrm{Mn}}^{2+}\right)$ ground state, electronic structure parameters have been obtained. In either case, the Mn $d$ electron number is evaluated to be $\sim 5$ using the obtained parameters, meaning that the neutral ${\mathrm{Mn}}^{3+}$ impurity, if it exists, consists of the Mn ${3d}^5$ configuration and a valence hole bound to it through $p-d$ hybridization and/or Coulomb interaction. We discuss the exchange interaction between the Mn local spin and the valence hole as well as the stability of the neutral impurity against the ionization of the valence hole.