Step energies and step-step interactions on vicinal surfaces of Rh and Pd

The calculation of step energies and a fortiori of step-step interactions i n transition metals remains up to now out of reach of ab initio methods. Us ing a tight-binding model in a s. p and d orbital basis set we have studied the energetics of several vicinal surfaces of Rh and Pd with (111), (100) and (110) terrace orientations. The energy per step atom exhibits a damped oscillatory behaviour as a function of the terrace width. This reveals the existence of oscillatory electronic step-step interactions that are strongl y dependent on the geometry and on the element and are of the same order of magnitude as other interactions. The possible existence of a magnetic mome nt in the vicinity of the step edges is also discussed. (C) 2001 Elsevier S cience B.V. All rights reserved.