화학공학소재연구정보센터
Applied Surface Science, Vol.219, No.1-2, 129-135, 2003
Relative stability of missing-row reconstructed (110) surfaces of noble metals
The missing-row reconstruction has been observed experimentally on clean An, Pt and Ir, while Cu and Ag are dormant cases in that the reconstruction can be provoked only by modest alkali coverage. The experimentally observed deconstruction and roughing transitions of Au(I 1 0) and Pt(l 1 0) are interesting realizations of two-dimensional Ising and XY models. The detailed understanding of the structures and energies of the missing-row configurations is also important for the constructions of many-atom model such as the embedded-atom potentials. We have carried out density-functional molecular-dynamics calculations for the missing-row reconstructed (I x 2), (1 x 3), and (I x infinity) surfaces. The calculation results show that the delocalization of d-electrons and the accumulation of sp-electrons near the surface associated with the multilayer relaxation are important factors in stabilizing the experimentally observed (I x 2) missing-row structure for Au and Pt. For Ir(l 1 0), a faceted (3 3 1) surface is shown to be the lowest energy configuration, in agreement with experimental observation. These results shed light on the relative stability of the missing-row configurations, and are useful for the construction of improved semi-empirical potentials, especially for the long range interaction. (C) 2003 Published by Elsevier Science B.V.