Inelastic Decay of Electrons in the Shockley-type Metal-Organic Interface States

We present a theoretical study of lifetimes of interface states (IS) on metal-organic interfaces PTCDA/Ag(111), NTCDA/Ag(111), PFP/Ag(111), and PTCDA/Ag(100), describing and explaining the recent experimental data. By means of unfolding the band structure of one of the interfaces under study onto the Ag(111) Brillouin zone we demonstrate, that the Brillouin zone folding upon organic monolayer deposition plays a minor role in the phase space for electron decay, and hence weakly affects the resulting lifetimes. The presence of the unoccupied molecular states below the IS gives a small contribution to the IS decay rate mostly determined by the change of the phase space of bulk states upon the energy shift of the IS. The calculated lifetimes follow the experimentally observed trends. In particular, we explain the trend of the unusual increase of the IS lifetimes with rising temperature.Comment: 8 pages, 5 figure

The 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 non-locality of many-electron interactions near the surface yields surprisingly long image-state lifetimes, in agreement with experiment.Comment: 4 pages, 2 figures, to appear in Phys. Rev. Let

Lifetimes of electrons in the Shockley surface state band of Ag(111)

We present a theoretical many-body analysis of the electron-electron (e-e) inelastic damping rate $\Gamma$ of electron-like excitations in the Shockley surface state band of Ag(111). It takes into account ab-initio band structures for both bulk and surface states. $\Gamma$ is found to increase more rapidly as a function of surface state energy E than previously reported, thus leading to an improved agreement with experimental data

Interplay between exchange-split Dirac and Rashba-type surface states at the MnBi2Te4/BiTeI interface

Based on ab initio calculations, we study the electronic structure of the BiTeI/MnBi2Te4 heterostructure interface composed of the antiferromagnetic topological insulator MnBi2Te4 and the polar semiconductor trilayer BiTeI. We found a significant difference in the electronic properties of the different contacts between the substrate and overlayer. While the case of a Te-Te interface forms a natural expansion of the substrate, when the Dirac cone state locates mostly in the polar overlayer region and undergoes a slight exchange splitting, the Te-I contact is the source of a four-band state contributed by the substrate Dirac cone and Rashba-type state of the polar trilayer. Owing to magnetic proximity, the pair of Kramers degeneracies for this state is lifted, which produces a Hall response in the transport regime. We believe our findings provide new opportunities to construct novel spintronic devices

Acoustic surface plasmons in the noble metals Cu, Ag, and Au

We have performed self-consistent calculations of the dynamical response of the (111) surface of the noble metals Cu, Ag, and Au. Our results indicate that the partially occupied surface-state band in these materials yields the existence of acoustic surface plasmons with linear dispersion at small wave vectors. Here we demonstrate that the sound velocity of these low-energy collective excitations, which had already been predicted to exist in the case of Be(0001), is dictated not only by the Fermi velocity of the two-dimensional surface-state band but also by the nature of the decay and penetration of the surface-state orbitals into the solid. Our linewidth calculations indicate that acoustic surface plasmons should be well defined in the energy range from zero to $\sim 400$ meV.Comment: 8 pages, two columns, 7 figures, to appear in Phys. Rev.

Excitation of soft dipole modes in electron scattering

The excitation of soft dipole modes in light nuclei via inelastic electron scattering is investigated. I show that, under the proposed conditions of the forthcoming electron-ion colliders, the scattering cross sections have a direct relation to the scattering by real photons. The advantages of electron scattering over other electromagnetic probes is explored. The response functions for direct breakup are studied with few-body models. The dependence upon final state interactions is discussed. A comparison between direct breakup and collective models is performed. The results of this investigation are important for the planned electron-ion colliders at the GSI and RIKEN facilities.Comment: 23 pages, 8 figures, to be published in Physical Review

First principles quasiparticle damping rates in bulk lead

First principles calculations of the damping rates (inverse inelastic lifetimes) of low energy quasiparticles in bulk Pb are presented. Damping rates are obtained both for excited electrons and holes with energies up to 8 eV on a set of k vectors throughout the Brillouin zone (BZ). Strong localization effects in the calculated lifetimes are found. Averaged over the BZ inelastic lifetimes versus quasiparticle energy are reported as well. In addition, the effect of the spin-orbit induced splitting in the band structure on the calculated lifetimes in Pb is investigated.Comment: 10 pages, 8 figures, 5 table