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Abstract: The structure and morphology of pentacene films grown on a Cu(221) vicinal surface have been studied by means of scanning tunneling microscopy (STM), low energy electron diffraction (LEED) and atomic force microscopy (AFM). Well ordered saturated monolayer films were prepared by first depositing few nanometers pentacene at room temperature followed by brief heating above 400K in order to sublimate the multilayer excess. The chemisorbed monolayer adopts a (1×7) superstructure with a uniform alignment of the molecules along the step edges while upon further deposition this template induced ordering is not transferred to multilayer films. Instead the molecules continue to grow in an upright orientation and form pyramidal islands without any substrate related azimuthal orientation. [Copyright &y& Elsevier]

Abstract: Continuous crystalline MnSi ultrathin films with atomically flat surfaces, which are highly expected to find an application in Si-based spintronics, are grown on Si(111)- by solid phase epitaxy method. The interfacial reaction between Mn and Si and the formation processes of the films as well as their morphological variation with annealing temperature are investigated using scanning tunneling microscopy. The MnSi ultrathin films form in a two-dimensional (2D) fractal-like mode only at a Mn coverage above ∼2 ML and at an annealing temperature in the narrow range of ∼250–300 °C. Above ∼300 °C, the growth mode gradually transforms into Volmer–Weber mode and correspondingly, the continuous films transform into 2D compact islands. The films grow with a thickness unit of quadruple layer, which is consistent with the B20-type MnSi structure. [ABSTRACT FROM AUTHOR]

Abstract: Ordering of submonolayer iron phthalocyanine (FePc) molecules deposited on Ag(111) was investigated using scanning tunneling microscopy. The room temperature deposition of FePc alone, without any annealing, results in no ordered overlayers. However, posterior annealing the substrate to 475K leads to the formation of a two-dimensional oblique lattice with the lattice constants of 16.2±0.3Å and the angle of 78±1° between them. The resulting FePc lattice is commensurate to the substrate lattice. In addition, the nearest neighbor distance in the lattice is significantly increased through a distinctive molecular orientation of the FePc molecules within the unit cell. The commensurate lattice with a large intermolecular distance is in sharp contrast to that observed from a close-packed square lattice that many other metallo-phthalocyanine molecules often self-assemble into. A possible reasoning behind this intriguing structure is discussed. [Copyright &y& Elsevier]

Abstract: This study investigates ultra-thin potassium chloride (KCl) films on the Si(100)-2×1 surfaces at near room temperature. The atomic structure and growth mode of this ionic solid film on the covalent bonded semiconductor surface is examined by synchrotron radiation core level photoemission, scanning tunneling microscopy and ab initio calculations. The Si 2p, K 3p and Cl 2p core level spectra together indicate that adsorbed KCl molecules at submonolayer coverage partially dissociate and that KCl overlayers above one monolayer (ML) have similar features in the valance band density of states as those of the bulk KCl crystal. STM results reveal a novel c(4×4) structure at 1ML coverage. Ab initio calculations show that a model that comprises a periodic pyramidal geometry is consistent with experimental results. [Copyright &y& Elsevier]

Abstract: The solid-phase epitaxial growth process and surface structure of MnSi on Si(111) were investigated by coaxial impact-collision ion scattering spectroscopy (CAICISS) and atomic force microscopy (AFM). For the Si(111) sample deposited with 30 monolayers (ML) of Mn at room temperature, the intermixing of Mn and Si gradually started at 100°C and reached equilibrium at approximately 400°C. At this equilibrium state, the Mn atoms were transformed into crystalline MnSi film. Further annealing caused the desorption of Mn atoms. We identified the structure of MnSi as cubic B20 and the crystallographic orientation relationships as Si(111)//MnSi(111) and Si[]//MnSi[]. The MnSi(111) surface was found to have a dense Si terminating layer on its topmost surface. On the other hand, 3ML of Mn deposited on Si(111) reacted with Si even at room temperature and formed a pseudomorphic structure. This structure was transformed into MnSi after annealing. A filmlike morphology with protrusions was observed for the sample with 30ML of Mn, while island growth occurred for the sample with 3ML of Mn. [Copyright &y& Elsevier]

Abstract: The growth mechanisms and surface morphology of colossal magnetoresistance (CMR) La0.67Ca0.33MnO3 films deposited by rf magnetron sputtering on SrTiO3(001) substrates are investigated. The films are epitaxial, coherently strained and ferromagnetic. It is found that at early growth stages, in nanometric films, a layer-by-layer mechanism dominates, which results in step and terrace surface morphology. Upon further growth, the flat surface becomes unstable when large two-dimensional (2D) islands form. The Erlich-Schwoebel step-edge energy barrier induces an anisotropic adatom kinetics that favors 2D nucleation on top of the islands as it reduces downhill adatom current. As a result, there is an evolution with growth to mound-like structures of increasing height. Critical thickness for mound formation and average mound separation can be tuned by substrate miscut angle and growth temperature. These results provide a detailed understanding of the roughening process in manganites and are relevant for the controlled fabrication of CMR films, in particular for its use in epitaxial heterostructures. [Copyright &y& Elsevier]

Abstract: Growth modes of Co thin films on the both N-saturated and partially N-adsorbed Cu(001) surfaces are studied in detail. From results of the STM and XPS measurements, segregation of N atoms depending on the Co island size is concluded. This new type of atom segregation is explained by means of a lattice strain of the substrate due to the small Co island formation. A novel core-level shift of N1s during the Co film growth is also reported. A possible influence of the lattice strain to the electronic structure of the surfactant is discussed. [Copyright &y& Elsevier]