Coverage-dependent faceting of Au chains on Si(557)

Identification of the Au Coverage and Structure of theAu/Si(111)−(5×2)Surface

“…The incorporation of one more Au atom is not only a simple way of transforming into a desirable 5×2 structure but also could possibly be a physical realization of the idea of electron doping given by EBH. The resulting seven Au atoms per 5×2 cell, which is referred to as 0.7 ML, is slightly out of the experimental estimations of 0.56-0.67 ML [17][18][19] but is worth examining in light that a higher calibration of 0.65-0.67 ML is the latest result of a low-energy electron diffraction and microscopy study [19]. Figure 1(b) shows the lowest-energy structure where the added Au atom prefers to adsorb on a hollow site between the 1st and 2nd Au rows with at least 0.62 eV more gain in adsorption energy than other sites.…”

“…Figure 1(a) shows the best structural model so far, proposed by a combined theoretical-experimental study of Erwin, Barke, and Himpsel (hereafter, EBH) in 2009 [25]. It features a Si honeycomb chain and an Au triple chain and contains six Au atoms and twelve top-layer Si atoms in a 5×2 unit cell, well reflecting the experimental estimations of 5.6-6.7 Au atoms [17][18][19] and 11-14 Si atoms [28,29]. The EBH model was recently challenged by a new model derived by Abukawa and Nishigaya (hereafter, AN) in a reflection high-energy electron diffraction (RHEED) study [26].…”

“…Its atomic structure, however, is not yet solved in spite of extensive experimental studies [8][9][10][11][12][13][14][15][16][17][18][19] and density functional theory (DFT) calculations [20][21][22][23][24][25]. This long-standing surface science problem is thus considered a touchstone of our ability to look into the structure of complex surface/nano systems at truly atomic scale.…”

“…Bc, 73.20.At, 81.07.Vb The Au/Si(111)-5×2 surface is a representative selforganized one-dimensional (1D) metal chain system [1][2][3][4] and has served as a rich source of intriguing 1D phenomena such as atomic-scale Schottky barriers [5], 1D domain-wall hoppings [6], and confined doping on a metallic chain [7]. Its atomic structure, however, is not yet solved in spite of extensive experimental studies [8][9][10][11][12][13][14][15][16][17][18][19] and density functional theory (DFT) calculations [20][21][22][23][24][25]. This long-standing surface science problem is thus considered a touchstone of our ability to look into the structure of complex surface/nano systems at truly atomic scale.…”

New evidence for the influence of step morphology on the formation of Au atomic chains on vicinal Si(111) surfaces

“…1, bottom) [3]. A key driver for the triple-chain model was a (a) E-mail: jmcgilp@tcd.ie new coverage determination of 0.6 ML Au for the Si(111)-5 × 2-Au reconstruction [6]. These careful measurements used as a reference the simpler single-Au-chain structure of Si(557)-Au, which is generally agreed to have a Au coverage of 0.18 ML relative to the Si(111) surface ( fig.…”