Biomedical subjects

A Liebsch

Publications and source records attributed to A Liebsch.

At least 19 recordsLinked to original sources

PubMed2003

Surface versus bulk Coulomb correlations in photoemission spectra of SrVO3 and CaVO3.

Recent photoemission spectra of the perovskite series CaxSr1-xVO3 revealed strong modifications associated with surface contributions. To study the effect of Coulomb correlations in the bulk and at the surface, the quasiparticle spectra are evaluated using the dynamical mean field theory. It is shown that as a result of the reduced coordination number of surface atoms correlation effects are stronger at the surface than in the bulk, in agreement with experiment.

Journal Article↗

PubMed2002

Role of surface plasmons in the decay of image-potential States on silver surfaces.

The combined effect of single-particle and collective surface excitations in the decay of image-potential states on Ag surfaces is investigated, and the origin of the long-standing discrepancy between experimental measurements and previous theoretical predictions for the lifetime of these states is elucidated. Although surface-plasmon excitation had been expected to reduce the image-state lifetime, we demonstrate that the subtle combination of the spatial variation of s-d polarization in Ag and the characteristic nonlocality of many-electron interactions near the surface yields surprisingly long image-state lifetimes, in agreement with experiment.

Journal Article↗

PubMed2001

Comment on "Fermi surface, surface states, and surface reconstruction in Sr(2)RuO(4)".

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Letter↗

PubMed2001

Quantum well behavior without confining barrier observed via dynamically screened photon field.

Angle-resolved photoemission spectra from Na adlayers on Al(111) reveal features which behave like quantum well resonances although the substrate provides no confining barrier. These features are observed in a narrow photon energy range where overlayer collective excitations cause resonant enhancement of the photoemission intensity. The quantum well behavior is shown to be due to surface resonances of the Na/Al system. The resonances are observable using photoemission because of spatial confinement and dynamical enhancement of the local electric field within the Na films.

Journal Article↗

PubMed2000

Photoemission quasiparticle spectra of Sr2RuO4

Multiband quasiparticle calculations based on perturbation theory and dynamical mean-field methods show that the creation of a photoemission hole state in Sr2RuO4 is associated with a highly anisotropic self-energy. Since the narrow Ru-derived d(xz,yz) bands are more strongly distorted by Coulomb correlations than the wide d(xy) band, charge is partially transferred from d(xz,yz) to d(xy), thereby shifting the d(xy) Van Hove singularity close to the Fermi level.

Journal Article↗

PubMed1996