Ab initio simulations of structural and optical properties of Au-stabilized Si(hhl) surfaces

The adsorption of gold on flat and stepped Si(111) surfaces induces regular and spatially-dense nanostructure arrays, through formation of single or multiple atomic Au chains within the terraces as well as rows of Si dangling bonds and honeycomb structures at the step edge [1]. These reconstructions constitute a well-defined prototype for studying a range of interesting phenomena in (quasi-)one dimensional systems including metal-insulator transitions, long-range spin order, Rashba splitting, and spin chain manipulation [2,3]. Ab initio simulations have been used to predict surface structure, investigate such phenomena and interpret experimental results [4,5]. One such technique that offers precise microscopic insight is reflectance anisotropy spectroscopy (RAS), which is particularly sensitive to the intrinsically anisotropic nature of surface structural motifs (Au chains, spin chains, adatoms, and so on) [6,7]. In this presentation I will demonstrate how careful simulations of RAS experiments carried out within the FOR1700 network yields insight into structural and electronic phenomena in these systems and even how to control them externally [8]. [1] F. Himpsel et al, J. Phys.: Cond. Mat 13, 11097 (2001) [2] J. Aulbach, J. Schafer, S. C. Erwin, S. Meyer, C. Loho, J. Settelein, and R. Claessen, Physical Review Letters 111, 137203 (2013). [3] J. Aulbach, S. C. Erwin, R. Claessen, and J. Schafer, Nano Letters 16, 2698 (2016). [4] S. C. Erwin and F. J. Himpsel, Nature communications, 1, 58 (2010). [5] M. Krawiec, Physical Review B 81, 115436 (2010). [6] C. Hogan, N. McAlinden, J. McGilp, Phys Stat Sol B 249, 1095-1104 (2012) [7] C. Hogan, E. Ferraro, N. McAlinden, J. F. McGilp, Phys. Rev. Lett. 111, 087401 (2013). [8] C. Hogan, E. Speiser, S. Chandola, S. Suchkova, J. Aulbach, J. Schafer, S. Meyer, R. Claessen, and N. Esser, in preparation