Raman signature of electron-electron correlation in chemically doped few-layer graphene

We report an experimental Raman study of few-layer graphene after chemical doping achieved by a plasma process in CHF$_3$ gas. A systematic reduction of both the splitting and the area of the 2D band is observed with increasing the doping level. Both effects can be ascribed to the electron-electron correlation, which on the one hand reduces the electron-phonon coupling strength, and on the other hand affects the probability of the double resonant Raman process

Huge (but finite) time scales in slow relaxations: beyond simple aging

Experiments performed in the last years demonstrated slow relaxations and aging in the conductance of a large variety of materials. Here, we present experimental and theoretical results for conductance relaxation and aging for the case-study example of porous silicon. The relaxations are experimentally observed even at room temperature over timescales of hours, and when a strong electric field is applied for a time $t_w$, the ensuing relaxation depends on $t_w$. We derive a theoretical curve and show that all experimental data collapse onto it with a single timescale as a fitting parameter. This timescale is found to be of the order of thousands of seconds at room temperature. The generic theory suggested is not fine-tuned to porous silicon, and thus we believe the results should be universal, and the presented method should be applicable for many other systems manifesting memory and other glassy effects.Comment: 4+ pages, 4 figure

THE RELATIONSHIP BETWEEN STRATEGIC BUSINESS UNITS, SUBSIDIARY AND HEADQUARTER IN THE KNOWLEDGE MANAGEMENT OF THE MULTINATIONAL CORPORATION

The main objective of the paper is analysis the structure of the strategic business units (SBUs) of foreign subsidiaries in order to discover if they are fit to knowledge creation and dissemination to other subsidiaries and headquarter. Some international studies already discussed the subject, but the focus was the whole subsidiary and it was not the SBUs. This different approach shows the paper relevance and newness. It was researched thee companies: two foreign subsidiaries and one offshore operation. The results show some considerations to academic literature. The SBUs focus show that the relationship between headquarter and subsidiary is not the positive to the knowledge transference in all moments. The organizational structure troubles are the reason of this lack in the knowledge transference. In other way, alternative structures like offshore operations.O objetivo do estudo é analisar se a estrutura das unidades estratégicas de negócios (UENs) das filiais de multinacionais favorecem a criação e disseminação conhecimento para as demais UENs da própria subsidiária, de outras subsidiárias e para a matriz organizacional. Apesar de alguns trabalhos internacionais e nacionais abordarem o assunto, o enfoque analítico do presente texto é inédito, pois o foco da discussão não é a subsidiária e matriz da empresa multinacional, mas as UENs dessas empresas e suas relações no contexto internacional da rede multinacional. Foram realizados três estudos de caso: dois em subsidiárias de empresas multinacionais e outro em uma operação offshore da multinacional. Os resultados levantam inferências interessantes para literatura da área. O enfoque em UENs mostra que uma eficaz relação matriz e subsidiárias nem sempre consolida a transferência do conhecimento como postulado. As observações mostram que as falhas estruturais internas de determinada UEN sobrepõem o poder da relação matriz-subsidiárias na transferência do conhecimento. Outro ponto interessante é a relevância de contextos organizacionais alternativos para a criação e disseminação do conhecimento, contrário ao estabelecimento de uma estrutura formal da gestão do conhecimento

Modification of the electrical and optical Properties of Single Crystal Diamond with Focused MeV Ion Beams

AbstractIn this paper an overview is given on recent results obtained in the framework of an Italian/Croatian collaboration aimed to explore the potential of techniques based on focused MeV ion beams to locally modify the structural, electrical and optical features of diamond.Experiments were carried out using light (H, He, C) ion beams with energies of the order of MeV, focused to micrometer-size spot and raster scanned onto the surface of monocrystalline (IIa or Ib) diamond samples. Different energies, ion species and fluences were used, in conjunction with variable thickness masks and post annealing processes, to define three-dimensional structures in diamond, whose electrical/optical/structural properties have been suitably characterized. Finite element numerical methods have been employed in the modeling of the material modification and in device design

Optical constants of graphene layers in the visible range

We show that the optical constants of graphene in the visible range can be estimated by means of a very simple procedure involving their consistence with universal optical conductivity and experimentally measured optical spectra, within the framework of Fresnel coefficients calculation. The obtained complex refractive index allows for accurate prediction of the optical behavior of graphene in the visible range, from the two-dimensional limit (single atomically thick graphene layer) to the bulk limit (graphite). Therefore, it may result very useful for quantitative optical analysis of graphene layers and graphitic structures in genera

Common Format for Quantum Chemistry Interoperability: Q5Cost Format and Library

International audienc

Acetone-water complexes at MRCI level using localized orbitals: n → π∗ and π → π∗ electronic transitions

International audienceThe n → π∗ and π → π∗ vertical electronic transitions of acetone with two and four H2O which correspond to a first solvation shell are considered. By using localized orbitals, and thanks to the MRCI approach which permits to know the wave function, the role of the various solvent molecules is analysed in details. Distinguishing the solvent molecules allows one to consider them at different calculation levels. The methodology is to compare the spectra obtained with four H2O, with two H2O either in the acetone plane or in a perpendicular plane and when they are completely or partly frozen