[en] Atom by atom control over the local work function of a surface has been performed by using the tip of a scanning tunneling microscope to move and pin individual promoter atoms at predetermined atomic sites on the surface. Both positive and negative local work-function changes could be achieved, depending on the exact binding configuration of the pinned promoter atoms. This manipulation of individual promoter atoms has been exploited for testing the fabrication of atomic-scale chemical 'seeds.'

[en] Powering and controlling the operation of a single molecule adsorbed on a surface can be achieved by using the tip of a scanning tunnelling microscope (STM) as an atomic-size source of electrons. We review the various electronic excitation processes induced by the electrons from the STM tip which are able to activate the functions of a molecular nanomachine. In particular, we review recent results illustrating the electronic control of molecular dynamics at the level of a single molecule

[en] We evaluate a novel implementation of a Self-Organizing Map (SOM) on a Graphics Processing Unit (GPU) cluster. Using various combinations of OpenCL, CUDA, and two different graphics cards, we demonstrate the scalability of the SOM implementation on one to eight GPUs. Results indicate that while the algorithm scales well with the number of training samples and the map size, the benefits from using the data-parallel approaches offered by the GPU are severely limited when combined with the Message Passing Interface (MPI) in this setting, and comparable to speedups of GPU-based implementations as compared to optimized sequential code. Speedups achieved range from 3 to 32, for various map and training data sizes. We also observed a performance penalty for the OpenCL implementation as compared to CUDA.

[en] In this paper we report on the first steps of silicene growth on Ag(111) using scanning tunneling microscopy. We show that the topmost atomic layer is composed of both silicon and silver. The STM observations are consistent with an exchange process between the silicon and silver atoms preferentially taking place at the step edges of the Ag substrate. In addition, silicon stripes are observed as precursors of the formation of the silicene sheet. (paper)

[en] The surface electronic structure of the hydrogenated diamond C(100)-(2x1):H surface was studied using scanning tunneling microscopy (STM), valence band and core-level photoemission, and near-edge x-ray-absorption fine structure. The hydrogenated diamond surface was prepared ex situ by hydrogen plasma treatment. The STM topographies of the hydrogenated diamond surface, recorded with an atomic resolution, indicated the atomically smooth diamond surface. The current-voltage (I-V) spectroscopy was used to study the transport of electrons injected from the STM tip into the diamond surface. It has been shown that the electron transport is determined not only by the surface states available but it depends crucially on the amount of subsurface hydrogen and the charge redistribution at the surface. Annealing of the diamond surface induces desorption of the subsurface hydrogen. That affects the electron transport as evidenced from the analysis of the I-V spectroscopy curves. A qualitative model for the electron transport, taking into account the specific electronic structure of the hydrogenated diamond surface, has been proposed

[en] The growth of silicene nano-ribbons (NRs) on Ag(110) substrate is re-investigated using scanning tunneling microscopy (STM) and low energy electron diffraction (LEED). Deposition of one silicon monolayer at 230°C induces the formation of one-dimensional 1.6 nm wide silicene nanoribbons into a well-ordered compact array with a nanometer-scale pitch of just 2 nm. Based on the STM analysis we derived an atomic model of the silicene nanoribbons (NRs) where they are substantially buckled, and quantum confinement of the electrons in the NRs contribute to electronic density of states.

[en] The deposition of one monolayer of silicon on a Ag(lll) substrate induces the formation of silicene structures exhibiting different ordered phases, including a (2√3x2√3)R30°, a (4×4) and a (√13x√13)R13.9° superstructures. In tms paper we focus on the (2√3x√3)R30° phase. Using a combination of scanning tunneling microscopy and LEED observations, we show that this phase corresponds to a 11° rotation of the silicene sheet relative to the substrate orientation.

[en] The synthesis of blue phosphorene by molecular beam epitaxy (MBE) has recently come under the spotlight due to its potential applications in electronic and optoelectronic devices. However, this synthesis remains a significant challenge. The surface reactivity between the P atoms and the Au atoms should be considered for the P/Au(111) system. In the MBE process, the temperature of the substrate is a key parameter for the growth of blue phosphorene. During the initial growth stage, irregularly shaped Phosphorus clusters grow on top of Au(111) surface at room temperature. When the substrate temperature is increased, these clusters transform into a phosphorene-like structure with a honeycomb lattice. An atom exchange reaction is observed between the P and first layer Au atoms under thermal activation at higher temperature, where the P atoms replace Au atoms to form a blue phosphorene structure within the top Au layer and at the step edges. (paper)

[en] We report on experimental evidence for the formation of a two dimensional Si/Au(110) surface alloy. In this study, we have used a combination of scanning tunneling microscopy, low energy electron diffraction, Auger electron spectroscopy, and ab initio calculations based on density functional theory. A highly ordered and stable Si-Au surface alloy is observed subsequent to growth of a sub-monolayer of silicon on an Au(110) substrate kept above the eutectic temperature.

[en] Using scanning tunneling microscopy, low energy electron diffraction measurements, and ab initio calculations based on density functional theory, we present atomic models of the (√(13)×√(13))R13.9° silicene superstructure grown on Ag(1 1 1). The STM images reveal two co-existing atomic arrangements with two different orientations of the silicene sheet relative to the Ag(1 1 1) surface. DFT calculations with and without the inclusion of van der Waals interactions show corrugated Si atomic positions for both orientations implying a significant interaction with Ag(1 1 1) surface. The electronic structure of both silicene and Ag(1 1 1) surface are sufficiently affected that new interface states emerge close to the Fermi level.