First-principles study of the structural and electronic properties of the clean and O-deficient ZnAl2O4(111) surfaces

Abstract

In this study, the GGA-PBE method was used to study the structural and electronic properties of the ZnAl2O4(111) surface with and without oxygen vacancies. The ZnAl2O4(111) surface has six possible surface terminations called Zn(O2), Zn(Al), Al(Zn), Al(O2), O2(Zn), and O2(Al). The results obtained in this work show that the surface energy, electronic structure and work function of the ZnAl2O4(111) surface depend greatly on the nature of atoms in the top surface layer. The calculated surface energies indicate that the Zn(O2) termination is the most stable surface termination in O-rich and Al-poor environments, while the Al(Zn) termination is the most stable termination in Al-rich and O-poor environments. On the other hand, our results show that the formation of oxygen vacancies can greatly affect the stability of the ZnAl2O4(111) surface. We found that the O-deficient surface is more stable than the perfect surface in the case of O2(Zn) and O2(Al) surface terminations. In the case of other surface termination, the formation energy of VO is positive under both O-rich and O-poor conditions except the case of the Zn(O2) termination under O-poor and Al-rich conditions. Moreover, we found that the formation of oxygen vacancies can greatly affect the stability, electronic structure, and work function of the ZnAl2O4(111) surface.