LDA+U calculated electronic and structural properties of NiO(001) and NiO(111) p(2 x 2) surfaces

In this work, the reconstruction effects for NiO(00 1) and oxygen terminated NiO(I 1 1) p(2 x 2) surfaces have been investigated. The projector augmented wave method together with the Car-Parrinello molecular dynamics scheme have been used to determine the atomic geometry and electronic ground state. The correlation effects of the Ni d electrons are treated using a meanfield multi-orbital Hubbard correction, the so-called LDA + U approximation, to the local spin density Hamiltonian (where LDA stands for the local-density approximation and U for the Hubbard interaction). The LDA + U calculation shows that the reconstruction effects as well as the changes of the electronic structure of the NiO(001) surface are small compared to the unreconstructed surface. On the contrary, the oxygen-terminated NiO(l 1 1) p(2 x 2) polar surface exhibits important reconstruction effects and changes of the electronic structure, that provide additional stabilization of this polar surface. (C) 2002 Published by Elsevier Science B.V.