First-principles local density-functional electronic structure calculations were made of the (111) and (¯1¯1¯1) surfaces of the cubic phase. The energetically stable reconstructions: N adatom and N3 triangle on (111) and 2 x 1, B and N triangles on (¯1¯1¯1), were investigated. In the case of N adatoms on the (111) surface, 3 of the 4 dangling-bond states were removed from the surface model. In the case of N3 triangles on the (111) surface, 3 of the 4 dangling-bond states were removed because of the formation of bonds between the triangle N atoms and the surface N atoms. The remaining dangling-bond state, that was localized on the isolated surface B atom, appeared above the Fermi level. The energy of the states localized on the triangle-N atoms changed, when compared with the N3 triangle. In the case of B on the (¯1¯1¯1) surface, 1 dangling bond remained in the (2 x 2) unit cell that was localized on the isolated surface-N atom. The other 3 were removed because of interaction with the B3 triangle. The sp bonding state which corresponded to the bond between triangle B and surface N atoms appeared below the valence p-band. The stability of the (2 x 1) reconstruction on the (111) surface was attributed to the partial removal of the dangling-bond states and to the formation of π-bonds between upper-chain B and N atoms. In the case of the N triangle on the (¯1¯1¯1) surface, 3 of the 4 dangling-bond states disappeared because of the formation of bonds between triangle N and surface N atoms. The remaining one (localized on the isolated surface-N) appeared below the Fermi level and was doubly occupied.

Electronic Structure of the (111) and (¯1¯1¯1) Surfaces of Cubic BN: a Local Density Functional ab initio Study. K.Kádas, G.Kern, J.Hafner: Physical Review B, 1999, 60[12], 8719-26