Relaxation of the (0 0 1) surface in binary Sc, Ti and V nitrides: a first principles density functional study

✍ Scribed by Norge Cruz Hernández; Jesús Graciani; Javier Fdez. Sanz

• Publisher: Elsevier Science
• Year: 2003
• Tongue: English
• Weight: 151 KB
• Volume: 541
• Category: Article
• ISSN: 0039-6028
• DOI: 10.1016/s0039-6028(03)00927-0

✦ Synopsis

Density functional calculations with periodic boundary conditions of the structure of ScN, TiN and VN(0 0 1) surfaces are reported. Using slabs of different thickness to model the surface, the rippling relaxation of outermost layer is estimated to be 0.011, 0.178 and 0.256 A A, respectively. Calculations show that on nitrogen atoms there is a significant surface core-level shift arising from both the lack of periodicity and the rippling relaxation. For the TiN(0 0 1) surface, the rippling contribution to the N 1s surface core-level shift is estimated to be )0.20 eV (35%), with a final value of )0.56 eV, in excellent agreement with photoemission experiments. The analysis of the electronic band structure of TiN(0 0 1) surface along the C-X and X -M directions confirms that the experimentally surface state observed in the angle-resolved photoemission spectra at )2.9 eV is due to a Tamm surface state pulled off the top of the D 5 bulk band. The shift of the state is also clearly enhanced by the rippling relaxation.