Language needs in business, a survey of european multinational companies

This survey of language needs was carried out to help create a better match between the actual use of foreign languages in their working environment and the training of future managers within the CEMS programme.language skills business; communication skills; multinational companies

Elementary structural building blocks encountered in silicon surface reconstructions

Driven by the reduction of dangling bonds and the minimization of surface stress, reconstruction of silicon surfaces leads to a striking diversity of outcomes. Despite this variety even very elaborate structures are generally comprised of a small number of structural building blocks. We here identify important elementary building blocks and discuss their integration into the structural models as well as their impact on the electronic structure of the surface

STM microscopy of the CDW in 1T-TiSe2 in the presence of single atom defects

We present a detailed low temperature scanning tunneling microscopy study of the commensurate charge density wave (CDW) in 1$T$-TiSe$_2$ in the presence of single atom defects. We find no significant modification of the CDW lattice in single crystals with native defects concentrations where some bulk probes already measure substantial reductions in the CDW phase transition signature. Systematic analysis of STM micrographs combined with density functional theory modelling of atomic defect patterns indicate that the observed CDW modulation lies in the Se surface layer. The defect patterns clearly show there are no 2$H$-polytype inclusions in the CDW phase, as previously found at room temperature [Titov A.N. et al, Phys. Sol. State 53, 1073 (2011). They further provide an alternative explanation for the chiral Friedel oscillations recently reported in this compound [J. Ishioka et al., Phys. Rev. B 84, 245125, (2011)].Comment: 5 pages, 4 figure

Spontaneous exciton condensation in 1T-TiSe2: a BCS-like approach

Recently strong evidence has been found in favor of a BCS-like condensation of excitons in 1\textit{T}-TiSe$_2$. Theoretical photoemission intensity maps have been generated by the spectral function calculated within the excitonic condensate phase model and set against experimental angle-resolved photoemission spectroscopy data. Here, the calculations in the framework of this model are presented in detail. They represent an extension of the original excitonic insulator phase model of J\'erome \textit{et al.} [Phys. Rev. {\bf 158}, 462 (1967)] to three dimensional and anisotropic band dispersions. A detailed analysis of its properties and further comparison with experiment are also discussedComment: Submitted to PRB, 11 pages, 7 figure

Doping nature of native defects in 1T-TiSe2

The transition metal dichalcogenide 1T-TiSe2 is a quasi two-dimensional layered material with a charge density wave (CDW) transition temperature of TCDW 200 K. Self-doping effects for crystals grown at different temperatures introduce structural defects, modify the temperature dependent resistivity and strongly perturbate the CDW phase. Here we study the structural and doping nature of such native defects combining scanning tunneling microscopy/spectroscopy and ab initio calculations. The dominant native single atom dopants we identify in our single crystals are intercalated Ti atoms, Se vacancies and Se substitutions by residual iodine and oxygen.Comment: 5 pages, 3 figure

A new structural model for the Si(331)-(12x1) reconstruction

A new structural model for the Si(331)-(12x1) reconstruction is proposed. Based on scanning tunneling microscopy images of unprecedented resolution, low-energy electron diffraction data, and first-principles total-energy calculations, we demonstrate that the reconstructed Si(331) surface shares the same elementary building blocks as the Si(110)-(16x2) surface, establishing the pentamer as a universal building block for complex silicon surface reconstructions

Temperature dependence of the excitonic insulator phase model in 1T-TiSe2

Recently, detailed calculations of the excitonic insulator phase model adapted to the case of 1\textit{T}-TiSe$_2$ have been presented. Through the spectral function theoretical photoemission intensity maps can be generated which are in very good agreement with experiment [Phys. Rev. Lett. {\bf 99}, (2007) 146403]. In this model, excitons condensate in a BCS-like manner and give rise to a charge density wave, characterized by an order parameter. Here, we assume an analytical form of the order parameter, allowing to perform temperature dependent calculations. The influence of this order parameter on the electronic spectral function, to be observed in photoemission spectra, is discussed. The resulting chemical potential shift and an estimation of the resistivity are also shown.Comment: 4 pages, 3 figures, paper submitted at the Strongly Correlated Electron System conference, Brazil, 200

Temperature dependent photoemission on 1T-TiSe2: Interpretation within the exciton condensate phase model

The charge density wave phase transition of 1T-TiSe2 is studied by angle-resolved photoemission over a wide temperature range. An important chemical potential shift which strongly evolves with temperature is evidenced. In the framework of the exciton condensate phase, the detailed temperature dependence of the associated order parameter is extracted. Having a mean-field-like behaviour at low temperature, it exhibits a non-zero value above the transition, interpreted as the signature of strong excitonic fluctuations, reminiscent of the pseudo-gap phase of high temperature superconductors. Integrated intensity around the Fermi level is found to display a trend similar to the measured resistivity and is discussed within the model.Comment: 8 pages, 6 figure

Excited states at interfaces of a metal-supported ultrathin oxide film

We report layer-resolved measurements of the unoccupied electronic structure of ultrathin MgO films grown on Ag(001). The metal-induced gap states at the metal/oxide interface, the oxide band gap, and a surface core exciton involving an image-potential state of the vacuum are revealed through resonant Auger spectroscopy of the MgKL23L23 Auger transition. Our results demonstrate how to obtain new insights on empty states at interfaces of metal-supported ultrathin oxide films