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Band Dispersion (band + dispersion)
Selected AbstractsAngle-resolved photoemission spectroscopy and imaging with a submicrometre probe at the SPECTROMICROSCOPY-3.2L beamline of ElettraJOURNAL OF SYNCHROTRON RADIATION, Issue 4 2010Pavel Dudin The extensive upgrade of the experimental end-station of the SPECTROMICROSCOPY-3.2L beamline at Elettra synchrotron light source is reported. After the upgrade, angle-resolved photoemission spectroscopy from a submicrometre spot and scanning microscopy images monitoring the photoelectron signal inside selected acquisition angle and energy windows can be performed. As a test case, angle-resolved photoemission spectroscopy from single flakes of highly oriented pyrolitic graphite and imaging of the flakes with image contrast owing to rotation of the band dispersion of different flakes are presented. [source] Intermolecular band dispersion in highly ordered monolayer and multilayer films of pentacene on Cu(110)PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 5 2008Hiroyuki Yamane Abstract We report the electronic structure and the charge transport mechanism of highly ordered films of pentacene on Cu(110) surface studied by angle-resolved ultraviolet photoemission spectroscopy using synchrotron radiation. For a flat-lying monolayer film, we observed the evidences of (i) formation of the interface states and (ii) two-dimensional intermolecular band dispersion of the resultant interface states, which may originate from the hybridization between the molecular orbi-tals and the wave function of the substrate. For an upright-standing multilayer film, we observed the two-dimensional intermolecular band dispersion, which originates from the intermolecular ,,, interaction. The observed effective masses of the hole for different azimuths demonstrate the presence of the anisotropy of the hole mobility in pentacene crystals also at higher temperatures. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Theory of electronic structure of BGaAs and related alloysPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 2 2008A. Lindsay Abstract Previous experiments on BxGa1,xAs containing a few percent boron show a dramatic increase in electron effective mass, m*e, similar to that observed in many GaNxAs1,x samples. By contrast, there is a near-linear blue-shift of the energy gap, which can be conventionally described using the virtual crystal approximation. We use a tight-binding model to show that isolated B atoms have little effect either on the band gap or lowest conduction band dispersion in BxGa1,xAs. By contrast, B pairs and clusters introduce defect levels close to the conduction band edge (CBE) which, through a weak band-anticrossing (BAC) interaction, significantly reduce the band dispersion in and around the , -point, thus accounting for the strong increase in m*e and reduction in mobility observed in these alloys. Calculations show that replacing gallium by aluminium shifts the CBE upwards, leading to a large density of B-related states in the energy gap. By contrast, indium shifts the band edge downwards, leading eventually to a band edge m*e close to that predicted by the virtual crystal approximation. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | ||||||||||