Band-structure effects in photoelectron-emission spectra from metal surfaces

Motivated by the striking dependence of the valence electronic structure of transition metal surfaces on their crystallographic orientation, and by emerging experiments on laser-assisted extended ultraviolet (XUV) photoemission from solid surfaces, we calculate photoemission spectra from Cu(100) and Cu(111) surfaces as a function of the photoelectron final kinetic energy and the delay between the ionizing attosecond XUV pulse train and assisting infrared (IR) laser pulse. Our numerical simulations predict distinct differences in delaydependent photoelectron energy distributions and photoemission time delays for Cu(100) and Cu(111) surfaces. These differences can be scrutinized experimentally with existing technology in a suggested in situ comparative RABBITT (reconstruction of attosecond beating by interference of two-photon transitions) configuration by placing the two surfaces on a sliding platform while keeping all optical components and pathlengths fixed. Our calculations also show that the inclusion of the Fresnel-reflected incident IR pulse at the metal-vacuum interface modifies photoelectron spectra and photoemission time delays in a characteristic way that reveals the degree of spatial location of the initial electronic states.

Section: A Initial Statesmentioning

confidence: 99%

Comparative time-resolved photoemission from the Cu(100) and Cu(111) surfaces

Ambrosio

Thumm

2016

“…The exact quantitative description of photoemission from solid surfaces is more complicated than for isolated atoms due to their complex electronic band structure [3,14,15], elastic and inelastic collisions of photoreleased electrons inside the solid [16][17][18], the screening of the NIR streaking field in the solid [17,18], and surface and bulk plasmon excitations [19,20]. In the TDSE approach of Kazansky and Echenique [17], the valence-band (VB) initial states are modeled in terms of a "Chulkov potential" [21] and the corelevel (CL) initial states by combined Chulkov and Yukawa potentials.…”

Section: Introductionmentioning

confidence: 99%

Initial-state, mean-free-path, and skin-depth dependence of attosecond time-resolved IR-streaked XUV photoemission from single-crystalline magnesium

Liao

Thumm

2014

We analyze the dependence of attosecond streaked photoelectron spectra and photoemission time delays from valence band (VB) and 2p core-level (CL) states of a single-crystalline Mg(0001) thin film on the (i) modeling of the substrate electronic structure, (ii) electron mean free path (MFP), (iii) screening of the near-infrared (NIR) streaking laser field, and (iv) chirp of the attosecond extreme ultraviolet (XUV) pulse. Our quantum-mechanical numerical simulations predict streaked photoemission spectra that depend sensitively on the XUV chirp and weakly on the screening of the streaking laser field by the substrate. They furthermore show that streaking time delays for VB emission are relatively insensitive to the modeling of the initial quantum states, electron MFP, and NIR skin depth of the Mg substrate, in contrast to the stronger dependence of streaking time delays for 2p CL emission on these factors.

“…To describe the PE process we make use of a time-dependent distorted-wave method named bandstructure-based-Volkov (BSB-V) approximation [17]. The BSB-V approach includes an accurate description of the electron-surface interaction, given by the bandstructure-based (BSB) model [18], while the action of the laser field on the emitted electron is represented by means of the Volkov phase [19].…”

Section: Introductionmentioning

confidence: 99%

Induced-field enhancement of band-structure effects in photoelectron spectra from Al surfaces by ultrashort laser pulses

Rubiano

Picca

Mitnik³

et al. 2017

Self Cite

The influence of the crystallographic orientation of a typical metal surface, like aluminum, on electron emission spectra produced by grazing incidence of ultrashort laser pulses is investigated by using the band-structure-based-Volkov (BSB-V) approximation. The present version of the BSB-V approach includes not only a realistic description of the surface interaction, accounting for band structure effects, but also effects due to the induced potential that originates from the collective response of valence-band electrons to the external electromagnetic field. The model is applied to evaluate differential electron emission probabilities from the valence band of Al (100) and Al(111). For both crystallographic orientations, the contribution of partially occupied surface electronic states and the influence of the induced potential are separately analyzed as a function of the laser carrier frequency. We found that the induced potential strongly affects photoelectron emission distributions, opening a window to scrutinize band structure effects.