Electronic structure and spin-to-charge conversion in the chalcopyrite ${\mathrm{CdGeAs}}_{2}$

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We have investigated by angle-resolved photoemission spectroscopy changes induced by Xe adsorption on the spin-orbit-split bands of the epitaxial Ag(111) (root 3x root 3)R30 degrees-Bi surface alloy. We observe an extensive backfolding of the alloy band structure due to the formation of a 9 x 9 commensurate or quasicommensurate Xe overlayer and the opening of a small hybridization gap at the intersection of two sets of bands of (primarily) Bi sp(z) and p(xy) characters. The large spin-orbit splitting of the

Experimental characterization is facing severe difficulties in elucidating the nature of defects at interfaces between silicon and amorphous high-kappa oxides. This motivates recourse to first principle simulation approaches based on density functional theory. A major issue for these approaches is the choice of the model structure. indeed, the most trivial choice of parent crystalline structures may fail in describing the amorphous nature of the oxide or the specific bonding arrangements occurring at the in

Positively charged defects induced by protons at the Si(100)-SiO2 interface are studied through density-functional calculations and realistic interface models. Protons generally preserve the bonding network, but cause the spontaneous breaking of strained bonds leading to threefold-coordinated Si(3)(+) and O(3)(+). Defect energies fall within a band of similar to 0.5 eV, which is stabilized by similar to 0.3 eV at the interface. Only the O(3)(+) at similar to 1 eV lower energies stand out as deep defects. Th

We have investigated the doping mechanism of pentacene with iodine and its impact on the structure and on the electronic properties of single crystals, powders, and thin films in a large range of iodine concentration up to six iodine per pentacene (PEN) molecule (I/PEN = 6). Three regimes of doping have been identified. In the low doping regime I/PEN < 0.05, the pristine pentacene structure of single crystals is maintained. Electron spin resonance (ESR) evidences a Pauli susceptibility, that is, the charact

The reactivity of phenolic compounds can be drastically affected by the electronic nature of substituents and by their positions in the aromatic ring. In this work, structure effect on the photoreactivity via TiO2 catalysis is studied using several substituted phenols in order to cover a wide variety of electronic effects, ranging from strong electron-donating (activating) to strong electron-withdrawing (deactivating) groups: ---OH, ---OCH3, ---OCH2CH2CH3, ---COOH, ---COH, ---COCH3, ---NO2, ---SO3H, ---CN,

Novel x-ray spectroscopies such as high-resolution x-ray absorption (XAS) performed in the partial fluorescence yield mode (PFY), and resonant emission (RXES) offer new opportunities to probe the bulk electronic configuration in strongly correlated systems. We performed an Yb L-3 PFY-XAS and RXES investigation of the intermediate valence compound YbAl2 under external pressure. We found that the Yb valence increases from 2.25 at ambient pressure to 2.9 at 385 kbar. This experiment has extended the range of p

We analyze the electronic properties of quantum wires with a Z-like profile within four-band models for the valence band of a semiconductor of diamond and zinc blende type. Group-theoretical considerations show that the valence-band structure is doubly degenerate only when the linear k-terms (coming e.g. from the bulk crystal inversion asymmetry) are neglected. The considerations apply to the more general case of a profile containing a 2D center of inversion.

Using time-resolved photoluminescence, we have investigated the radiative behavior of neutral and negatively charged excitons in CdTe-based quantum wells. We find that the photoluminescence of negatively charged excitons can be well reproduced by a model of delocalized and thermalized three-particle complexes. A large radiative zone in k-space results from the transfer of the charged exciton momentum to the remaining electron (recoil effect). On the other hand, the photoluminescence decay of excitons is not

We report on carrier-induced effects on emission and absorption in forward biased GaAs/AlGaAs V-groove quantum wire (QWR) diodes observed using low-temperature (10 K) photoluminescence (PL), electroluminescence (EL) and PL excitation (PLE) spectroscopy. In the case of simultaneous electron-hole injection we observe a band-gap renormalization (BGR) of at least 5 meV for a carrier density of approximate to 10(6) cm(-1), by comparing high-density EL spectra with low-density PLE spectra. In the case of electron

We performed angle-resolved photoemission experiments on overdoped single crystal Bi2Sr2CaCu2O8+x samples with Tc values as low as 55K and very narrow transitions as measured by AC susceptibility. The photoemission data indicate the presence of a ''shadow'' peak in the quasiparticle spectral function A(omega) shifted by (pi, pi) from the conventional quasiparticle peak. The ratio of the shadow/quasiparticle peak amplitudes strongly increases with the binding energy. This is consistent with the idea that the

We report a modification by thin silicon nitride intralayers of the Au/n-GaAs)(100) Schottky barrier height. Thin intralayers were obtained by nitridation of evaporated Si films on decapped GaAs substrates in an argon-nitrogen mixture plasma. The nitridation was performed at a beam energy

We have studied the influence of Co and Ni doping on the electronic band structure and the transport properties of high-temperature superconductors. The doping has dramatic effects on both the normal and the superconducting state. Upon doping the residual resistivity increases strongly. For sufficiently high Co concentration the temperature dependence rho(T) turns from a simple linear dependence to one displaying a minimum around T-min = 190 K. This minimum is followed by an upturn (d rho/dT

Electronic structure and spin-to-charge conversion in the chalcopyrite ${\mathrm{CdGeAs}}_{2}$

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Effect of rare-gas adsorption on the spin-orbit split bands of a surface alloy: Xe on Ag(111)-(root 3 x root 3) R30 degrees-Bi

First principles investigation of defects at interfaces between silicon and amorphous high-kappa oxides

Proton-induced fixed positive charge at the Si(100)-SiO2 interface

Electronic and structural evidences for charge transfer and localization in iodine-doped pentacene

Structural properties and photoreactivity relationships of substituted phenols in TiO2 suspensions

Determination of pressure-induced valence changes in YbAl2 by resonant inelastic x-ray emission

The band structure of Z-like quantum wires

Negatively charged excitons in CdTe-based quantum wells: A time-resolved study

Carrier-induced effects on absorption and emission in V-groove quantum wire diodes

Shadow bands in overdoped Bi2Sr2CaCu2O8+x

Au/GaAs(100) interface Schottky barrier modification by a silicon nitride intralayer

Localization effects in Co- and Ni-doped Bi2Sr2CaCu2O8+gamma