Electronic structure of acceptor defects in (Zn,Mn)O and (Zn,Mn)(O,N)

摘要

Using first-principles density functional calculations, we study the electronic structure and magnetic properties of Mn-doped ZnO, wurtzite crystal structure, with various defects. This allows to understand and to explain the half-metallicity and the ferromagnetism stability, observed in Mn-doped ZnO with acceptor defects like Zn vacancies. The calculations were performed using the Korringa-Kohn-Rostoker method combined with the coherent potential approximation. Hydrogenation effects in (Zn,Mn)O and (Zn,Mn)(O,N) is also investigated with and without defects. This work presents detailed information about total, atom, and vacancy projected density of states functions, and magnetic moment for different atoms and defects in Mn-doped ZnO and N-codoped (Zn,Mn)O. The Curie temperature T_c is evaluated by using the mean field approximation. We show also that higher values of T_c are attained for high concentration of vacancy defects sites in (Zn,Mn)O and for small concentration of vacancy defects sites in (Zn,Mn)(O,N). Mechanism of exchange interaction between magnetic ions in Mn-doped ZnO and N-codoped_(Zn,Mn)O with and without defects is also investigated. Finally, we propose a model which describes the origin of strong ferromagnetism stability observed in p-type ZnO.