Energetics ofSradatom interactions on theMo(112)surface

Abstract

First-principles methods are used to investigate the formation and structure of the ordered phases of Sr atoms adsorbed on the furrowed Mo͑112͒ surface. The energetics of various commensurate and incommensurate adatom structures providing information on lateral interactions between adatoms is determined for coverages 0.11ഛ⌰ഛ1 monolayer. It is found that the binding energy of Sr atoms decreases with increasing coverage. The experimentally observed p͑8 ϫ 1͒ and p͑5 ϫ 1͒ adatom chains are found to belong to the most favored structures for ⌰Ͻ0.5. The energetic difference between these two structures amounts to 20 meV. The experimental work function variation with Sr adatom coverage is very well reproduced. The energy barriers for Sr diffusion along the atomic troughs are calculated and discussed.

Fermi surface of Mo(112) and indirect interaction between adsorbed atoms

“…(1) assuming, somewhat arbitrarily, the same amplitudes A of Friedel oscillations for screening electrons in different sheets of Fermi surface, and which were chosen to yield reasonable values of the lateral interactions. It should be noted also that the depth of the various minima of the potential found here are in agreement with results of DFT calculations by Kiejna and Nieminen [42]. It perhaps should be noted that these variations on the contour of this corrugated surface (the minima) are about an order of magnitude smaller than the depth of the potential relief along the furrows (see Figure 5b).…”

“…This is based on a depth of the potential relief for the diffusion of Sr adatoms along Mo(112) furrows as calculated by Kiejna and Nieminen [42], of order 0.08 eV. Therefore, at Sr coverages less than 1/9 of a monolayer, the formation of the p(9×1) structure should still be expected, while the p(5×1) structure will start to form for coverages above 1/9 monolayer.…”

New view of the occupied band structure of Mo(112)

“…The surface charge density of the Mo(112) substrate is a significant factor in the formation of well ordered quasi-one-dimensional structures such as seen for Li/Mo(112) [32,33], Sr/Mo(112) [34][35][36][37], Ba/Mo(112) [38] and Gd/Mo(112) [39], where overlayer systems have, in common, very large lateral distances between the adjacent atomic chains, favorable for the quasi-one-dimensionality [40]. Yet to understand the rich physics of these ordered quasione-dimensional overlayers, the details of the Mo(112) band structure must be understood and thus drives us to re-examine the band structure of Mo(112) in far greater detail than before.…”

Energetics of holmium adsorption on Mo(1 1 2) surface

“…It is interesting to compare E b of Ho with the binding energy of Sr calculated by Kiejna and Nieminen [26] (see Fig. 4) due to formation of long-periodic structures p(9 × 1) and p(5 × 1) in Sr/Mo(1 1 2) system [11].…”