Theoretical studies of electronic states and phonon modes on the TiC(001)(1 x 1) surface

Abstract

We present a comprehensive picture of structural and electronic properties of the TiC(001)(1 x 1) surface. Our investigations are based on first-principles calculations within the local-density approximation of the density-functional theory. Good agreement has been observed between our calculation and experimental data for the atomic geometry of the surface. In particular, the calculated bond lengths between the first-layer C and the second-layer Ti (d(1C)-(2Ti) = 2.188 angstrom) and between the first-layer Ti and the second-layer C (d(1Ti-2C) = 2.031 angstrom) are in good agreement with the corresponding experimental values of 2.25 angstrom and 2.14 angstrom, respectively. We have also identified surface electronic states and provided clear support for previously available photoemission measurements. We have further calculated surface phonon modes at the zone centre and at the zone-edge point X using a linear response scheme based on the ab initio pseudopotential method. Our calculated surface phonon results are in excellent agreement with electron energy loss spectroscopy results. (C) 2007 Elsevier B.V. All rights reserved.