Reconstruction of steps on the Cu(111) surface induced by sulfur

Abstract

Arich menagerie of structures is identified at 5Kfollowing adsorption of lowcoverages (≤0.05 monolayers) of S on Cu(111) at room temperature. This paper emphasizes the reconstructions at the steps. The A-type closepacked step has 1 row of S atoms along its lower edge, where S atoms occupy alternating pseudo-fourfoldhollow (p4fh) sites. Additionally, there are 2 rows of S atoms of equal density on the upper edge, bridging a row of extra Cu atoms, together creating an extended chain. The B-type close-packed step exhibits an even more complex reconstruction, in which triangle-shaped groups of Cu atoms shift out of their original sites and form a base for S adsorption at (mostly) 4fh sites. We propose a mechanism by which these triangles could generate Cu-S complexes and short chains like those observed on the terraces. PHYSICS 142, 194711 (2015) Reconstruction of steps on the Cu(111) surface induced by sulfur A rich menagerie of structures is identified at 5 K following adsorption of low coverages (≤0.05 monolayers) of S on Cu(111) at room temperature. This paper emphasizes the reconstructions at the steps. The A-type close-packed step has 1 row of S atoms along its lower edge, where S atoms occupy alternating pseudo-fourfold-hollow (p4fh) sites. Additionally, there are 2 rows of S atoms of equal density on the upper edge, bridging a row of extra Cu atoms, together creating an extended chain. The B-type close-packed step exhibits an even more complex reconstruction, in which triangle-shaped groups of Cu atoms shift out of their original sites and form a base for S adsorption at (mostly) 4fh sites. We propose a mechanism by which these triangles could generate Cu-S complexes and short chains like those observed on the terraces. C 2015 AIP Publishing LLC.[http://dx

Formation of Two‐Dimensional Copper Selenide on Cu(111) at Very Low Selenium Coverage

“…These are chains consisting of concatenated Cu 2 S 3 .A t0 .05 ML, Cu-S complexes are replacedb y al ow-density ( p 43 p 43)R AE 7.58 reconstruction. [17,21,22] The Cu 2 S 3 and chain structures are stabilized by al inear SÀCuÀS motif. [17,20] We do not observe analogous structures in the Cu-Se system,a lthough the p 3i slands incorporate both Cu and Se, as in the Cu-S complexes.…”

“…[17,21,22] The Cu 2 S 3 and chain structures are stabilized by al inear SÀCuÀS motif. [17,20] We do not observe analogous structures in the Cu-Se system,a lthough the p 3i slands incorporate both Cu and Se, as in the Cu-S complexes. It is likely that multiple factors contributet ot his difference.O ne is simply the lattice mismatch between Cu(111)a nd the chalcogenide CuX (X = S, Se), which is 14 %f or the sulfide [23] but only 11 %f or the selenide.…”

“…This is in contrast to S, which forms small complexes with Cu under comparableconditions on Cu(111). [17,20] Experimental and Computational Details…”

“…Se atoms are placed at p 3 a intervals on open steps to matcht he experimental data in Section 3.1 and at 2 a intervals on the close-packed steps to match prior observations for Sa dsorbed at dense steps of Cu(111). [17] We evaluate m Se 0 ,a sw ell as an additional chemicalpotential, m Se hkl ,defining the latter as [Eq. (2)]:…”

Oxygen and sulfur adsorption on vicinal surfaces of copper and silver: Preferred adsorption sites

“…Our confidence in the results from the present DFT calculations is based largely on past successes with adsorption of chalcogens on coinage metals, where detailed comparisons with high-quality experimental data served to indicate the successes or shortcomings of DFT. [14][15][16][17][18][19][20][21] Most notably, DFT successfully provided an interpretation of scanning tunneling microscopy (STM) data for sulfur adsorption and sulfurinduced reconstruction at steps on Cu(111), 18 for seleniuminduced faceting of steps on Cu(111), 15 and for adsorption of sulfur atoms at steps (without reconstruction or faceting) on Cu(100). 14 Various aspects of the experimental dataadsorption sites, coverage dependence, and image featureswere consistent with DFT results.…”