Figure 1

(Color online) Calculated structures for the ${\mathrm{H}}_8{\mathrm{Si}}_8{\mathrm{O}}_{12}$ adsorption models on a ${\mathrm{Si}}_9{\mathrm{H}}_{12}$ silicon dimer. (a) Monovertex attachment model. (b) Cracked cluster attachment model.Reuse & Permissions

Figure 2

(Color online) (a) The cluster model of the STM tip comprised of 24 tungsten atoms arranged in four layers in the (111) direction (lattice constant $3.19\mathrm{\AA }$). (b) LDOS plotted in the plane $3\mathrm{\AA }$ above the nuclear core of the tip apex atom over an integrated energy range of $1.5\mathrm{eV}$ (from $E_f–1.5\mathrm{eV}$ to $E_f$). (c) The calculated DOS of the tip cluster model.Reuse & Permissions

Figure 3

(Color online) (a), (b) Experimental and (c)–(f) simulated constant current STM images of an individual ${\mathrm{H}}_8{\mathrm{Si}}_8{\mathrm{O}}_{12}$ cluster chemisorbed to $\mathrm{Si}\left(100\right)\text{−}2\times 1$. All images are in a $26\mathrm{\AA }\times 26\mathrm{\AA }$ region. (a) Experimental filled-states image; $V_S=-1.5\mathrm{V}$, $I_{\mathrm{T}}=0.1\mathrm{nA}$. (b) Experimental empty-states image; $V_{\mathrm{S}}=+1.5\mathrm{V}$, $I_{\mathrm{T}}=0.1\mathrm{nA}$. (c) Simulated filled-states image of a monovertex-attached ${\mathrm{H}}_8{\mathrm{Si}}_8{\mathrm{O}}_{12}$ cluster; $V_{\mathrm{S}}=-1.5\mathrm{V}$, $I_{\mathrm{T}}=0.5\mathrm{nA}$. (d) Simulated empty-states image of a monovertex-attached ${\mathrm{H}}_8{\mathrm{Si}}_8{\mathrm{O}}_{12}$ cluster; $V_S=+1.5\mathrm{V}$, $I_T=0.5\mathrm{nA}$. (e) Simulated filled-states image of a ${\mathrm{H}}_8{\mathrm{Si}}_8{\mathrm{O}}_{12}$ cluster attached according to the cracked cluster model; $V_{\mathrm{S}}=-1.5\mathrm{V}$, $I_{\mathrm{T}}=0.5\mathrm{nA}$. (f) Simulated empty-states image of a ${\mathrm{H}}_8{\mathrm{Si}}_8{\mathrm{O}}_{12}$ cluster attached according to the cracked cluster model; $V_S=+1.5\mathrm{V}$, $I_T=0.5\mathrm{nA}$. (The disorder in the $\mathrm{Si}$ dimer rows near the cluster is not representative of the majority of images. This figure presents simultaneously acquired filled- and empty-states images that are over a somewhat defective region of the substrate.)Reuse & Permissions

Figure 4

(Color online) A comparison of experimental and simulated apparent cluster heights. (a) Filled-states STM image height profiles taken across a pair of cluster features oriented perpendicular to the dimer row direction in the experimental and simulated images reported in Figs. 3a, 3c. (b) Empty-states STM image height profiles taken across cluster features in Figs. 3b, 3d.Reuse & Permissions

Figure 5

(Color online) Calculated LDOS as a function of increasing distance normal to the $\mathrm{Si}\left(100\right)\text{−}2\times 1$ surface for the monovertex-attached ${\mathrm{H}}_8{\mathrm{Si}}_8{\mathrm{O}}_{12}$ cluster. The origin of the $x$-axis indicates the position of the silicon dimer atom in part (a). (a) LDOS of a silicon dimer atom. (b) LDOS of a top face ${\mathrm{H}}_8{\mathrm{Si}}_8{\mathrm{O}}_{12}$ cluster oxygen atom.Reuse & Permissions

Figure 6

(Color online) An investigation of STM convolution effects. All images are plotted in an $8\mathrm{\AA }\times 8\mathrm{\AA }$ region. (a) displays a molecular orbital consisting of two $s$-type atomic orbitals of dissimilar phases separated by a distance of $2\mathrm{\AA }$ as observed at a plane $3\mathrm{\AA }$ above the nuclear cores with positive and negative phases colored red and blue, respectively. (b) Simulated constant height STM image of part (a). (c) displays a molecular orbital consisting of two $s$-type atomic orbitals of the same phase separated by a distance of $2\mathrm{\AA }$ as observed at a plane $3\mathrm{\AA }$ above the nuclear cores. (d) Simulated constant height STM image of part (c). (e) The molecular orbital of a monovertex-attached cluster as observed at a plane $2\mathrm{\AA }$ above the oxygen atoms in the top face of the cluster. (f) Simulated constant height STM image of part (e).Reuse & Permissions