First-principles pseudopotential study of GaN and BN(110) surfaces

Using the first-principles pseudopotential LDA approach, we have performed calculations of the atomic and electronic structure of the (110) surface of the cubic phase of GaN and BN. It is found that these surfaces are charact erised by a much smaller rotation angle omega of the top atomic layer than many other III-V(IIO) surfaces. We have found a linear correlation between the relative vertical displacement of the cation and the anion on the surfa ce layer (Delta,(perpendicular to)) and the surface bond length of the III- V, II-VI and SIC compounds. In addition, we have studied the band structure addressing the influence of the degree of ionicity on the character of the surface states. (C) 1999 Elsevier Science B.V. All rights reserved.