Andrew Mayne

Scanning tunneling microscopy investigation of the C-terminated β-SiC(100) c(2 × 2) surface reconstruction : dimer orientation, defects and antiphase boundaries

Abstract We investigate β-SiC(100) c(2×2) surface reconstruction by atom-resolved scanning tunneling microscopy (filled and empty electronic states). The results indicate that, contrary to previous knowledge, the CC triple-bond dimers that compose this surface are asymmetric and all tilted in the same direction (i.e. not anticorrelated), which suggests a compressive stress along the dimer direction. We also identify two specific defects: double dimer lines that are at the origin of antiphase boundaries, and missing dimers. In the latter case, the two nearest dimer neighbors along the dimer row are found to undergo a significant charge redistribution, leading to one of them being tilted in the opposite direction.

Self-assembled molecular chains formed by selective adsorption of lead–phthalocyanine on InSb(100)-(4×2)/c(8×2)

We study the structure of ultra thin lead–phthalocyanine (PbPc) overlayers deposited on the indium terminated InSb(100)-(4×2)/c(8×2) reconstructed surface by low-energy electron diffraction and scanning tunneling microscopy. The diffraction pattern for the PbPc monolayer grown on this surface corresponds to a 4×3 structure. We show that this structure is induced by a selective adsorption of the PbPc molecules on the indium stripes of the InSb(100) substrate. The adsorption is dominated by the interaction between the central lead atom of the molecule and the topmost indium atoms of the surface.

Variable temperature STM studies of the adsorption of oxygen on the Si(1 1 1)-7 7 surface

The scanning tunnelling microscope (STM) has been used to study the adsorption at room (300 K) and low (30 K) temperature of oxygen on the Si(1 1 1)-7 � 7 surface. Subsequently, STM manipulation has been used to find out which of the observed sites can be modified (displacement, transformation, desorption). It was found that the adsorption is quite different at 30 K compared to 300 K and that the manipulation at room temperature is essential in the identification of the sites. These results are in general agreement with recent conclusions from theoretical work [Phys. Rev. Lett. 84 (2000) 1724] and synchrotron radiation experiments [Phys. Rev. B 65 (2002) 035315]. 2002 Elsevier Science B.V. All rights reserved.

Anchoring phthalocyanine molecules on the 6H‐SiC(0001)3×3 surface

The adsorption of individual metal-free phthalocyanine molecules on the 6H‐SiC(0001)3×3 surface was studied using the scanning tunneling microscope supported by density functional theory calculations. Phthalocyanine molecules were found to be chemisorbed through a reaction of two conjugated imide groups with two silicon adatoms. This type of anchoring opens numerous perspectives for the organic functionalization of a biocompatible wide band gap semiconductor.

Si/6H–SiC(0001): An unexpected cubic 4×3 Si phase overlayer

We investigate Si deposition on the 6H–SiC(0001) 3×3 surface reconstruction by atom-resolved scanning tunneling microscopy. Upon thermal annealing, the Si thin film forms an unexpected structure having dimer rows in a cubic 4×3 surface array. Such a 4×3 Si phase has a very open surface very likely being at the origin of the exceptionally high reactivity to oxygen of the Si/6H–SiC(0001) system. These findings are relevant in silicon carbide oxidation.

Atomic structure of the ()R30° of silicene on Ag(111) surface

The deposition of one monolayer of silicon on a Ag(lll) substrate induces the formation of silicene structures exhibiting different ordered phases, including a ()R30°, a (4×4) and a ()R13.9° superstructures. In tms paper we focus on the ()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.