Atomic structure and electronic properties of Ta(1 1 2) and W(1 1 2) surfaces

We present results of theoretical and experimental studies of the structural and electronic properties of Ta(1 1 2) and W(1 1 2) surfaces. Atomic geometries of these surfaces and their electronic structures have been obtained from the first-principles pseudo-potential calculations based on the density functional theory and the use of the plane wave basis set. In the experimental part of our studies we have performed measurements of the photofield emission spectroscopy. The calculated density-of-states distributions are compared and discussed with energy distributions of electrons extracted from photofield emission characteristics. The photofield emission spectra measured for the surface regions of considered systems present very dense structures of features, while the corresponding dependences obtained for the bulk have much more smooth shape. Experimental results correspond very well with calculated density-of-states distributions.