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Free electron model

About: Free electron model is a research topic. Over the lifetime, 4678 publications have been published within this topic receiving 103535 citations.


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TL;DR: In this article, parallel and perpendicular interfacial susceptibilities (ISs) were derived from experimental spectra in p- and s-polarization using an inversion procedure based on Kramers-Kronig transform.
Abstract: Plasmonics of Ag, Au, and Zn nanoparticles supported on Al2O3(0001), TiO2(110), and ZnO(0001) substrates has been probed by surface differential reflectivity spectroscopy (SDRS) during vapor deposition growth. Parallel and perpendicular interfacial susceptibilities (ISs), or “optical thicknesses”, which characterize only the dielectric response of the film, are derived from experimental spectra in p- and s-polarization using an inversion procedure based on Kramers–Kronig transform. The consistency of the approach is checked against sum rules. Plasmonic contributions are unraveled by decomposing ISs into damped oscillators and identified with the help of dielectric simulations of truncated supported spheres or spheroids. Beyond the common Drude behavior of Ag, Au, and Zn, the comparison between the three metals demonstrates the paramount role of interband transitions in the ISs profiles. While gold and silver show free electron plasmon modes, zinc exhibits polarization modes of bound electrons. However, de...

30 citations

Journal ArticleDOI
TL;DR: The basis for the analysis is a recently developed ab initio quantum Monte Carlo- (QMC) based machine learning representation of the static local field correction (LFC) which provides an accurate description of the dynamical density response function of the electron gas at the considered parameters.
Abstract: We investigate the energy-loss characteristics of an ion in warm dense matter (WDM) and dense plasmas concentrating on the influence of electronic correlations. The basis for our analysis is a recently developed ab initio quantum Monte Carlo- (QMC) based machine learning representation of the static local field correction (LFC) [Dornheim et al., J. Chem. Phys. 151, 194104 (2019)JCPSA60021-960610.1063/1.5123013], which provides an accurate description of the dynamical density response function of the electron gas at the considered parameters. We focus on the polarization-induced stopping power due to free electrons, the friction function, and the straggling rate. In addition, we compute the friction coefficient which constitutes a key quantity for the adequate Langevin dynamics simulation of ions. Considering typical experimental WDM parameters with partially degenerate electrons, we find that the friction coefficient is of the order of γ/ω_{pi}=0.01, where ω_{pi} is the ionic plasma frequency. This analysis is performed by comparing QMC-based data to results from the random-phase approximation (RPA), the Mermin dielectric function, and the Singwi-Tosi-Land-Sjolander (STLS) approximation. It is revealed that the widely used relaxation time approximation (Mermin dielectric function) has severe limitations regarding the description of the energy loss of ions in a correlated partially degenerate electrons gas. Moreover, by comparing QMC-based data with the results obtained using STLS, we find that the ion energy-loss properties are not sensitive to the inaccuracy of the static local field correction (LFC) at large wave numbers, k/k_{F}>2 (with k_{F} being the Fermi wave number), but that a correct description of the static LFC at k/k_{F}≲1.5 is important.

30 citations

Journal ArticleDOI
TL;DR: The field of free electron quantum optics (FEQO) with technologies at the interplay of lasers, electron matter waves, and nanostructures is reviewed in this article.
Abstract: In recent years laser light has been used to control the motion of electron waves. Electrons can now be diffracted by standing waves of light. Laser light in the vicinity of nanostructures is used to affect free electrons, for example, femto-second and atto-second laser-induced electrons are emitted from nanotips delivering coherent fast electron sources. Optical control of dispersion of the emitted electron waves, and optically controlled femto-second switches for ultrafast electron detection are proposed. The first steps towards electron accelerators and matter optics on-a-chip are now being taken. New research fields are driven by these new technologies. One example is the optical generation of electron pulses on-demand and quantum degenerate pulses. Another is the emerging development of interaction free electron microscopy. This review will focus on the field of free electron quantum optics with technologies at the interplay of lasers, electron matter waves, and nanostructures. Questions that motivate their development will also be addressed. This review will focus on the field of free electron quantum optics (FEQO) with technologies at the interplay of lasers, electron matter waves, and nanostructures. Recent developments that include laser generation, acceleration, coherent beam splitting, compression and detection of electron pulses with femto-second resolution are discussed. Some of the motivations for these developments concerning societal impact, finding solutions to long standing scientific problems, and speculative issues are indicated.

30 citations

10 Dec 1981
TL;DR: In this article, a completely quantum formalism has been developed to describe the high density plasma effects on fundamental atomic parameters, including level shifts, coefficients of transition probabilities, and electron collision cross sections.
Abstract: A completely quantum mechanical formalism has been developed to describe the high density plasma effects on fundamental atomic parameters. Both the bound and free electrons are treated by a method which in principle is similar to Hartree's self-consistent field method. The free plasma electrons' wave-function is obtained from the Schrodinger equation with the effective potential representing the spherically averaged Coulomb interaction with bound and free electrons. Results are given for level shifts, coefficients of transition probabilities, and electron collision cross sections of Ne(9+) for temperature and 200 and 500 e V for an electron density range of 1 - 6 x 10 to the 24th power/cc, and of Ar(17+) for temperatures of 1000 and 2000 eV and electron densities from 2 x 10 to the 25th power to 8 x 10 to the 25th power/cc. In the low-density region, level shifts are obtained for H and He+.

30 citations

Journal ArticleDOI
TL;DR: In this paper, the authors compared the Raman spectra of $n$-type GaN on GaAs with line-shape calculations for excitations of the free electron gas, and found that the spectral features in the frequency range of the optical phonons are well explained by plasmon-phonon scattering from an overdamped plasma system taking into account wave-vector nonconservation.
Abstract: Raman spectra of $n$-type GaN on GaAs are compared with line-shape calculations for excitations of the free electron gas. The spectral features in the frequency range of the optical phonons are well explained by plasmon-phonon scattering from an overdamped plasma system taking into account wave-vector nonconservation. The charge-density-fluctuation mechanism is found to be important for off-resonant excitation. For excitation closer to the fundamental band gap of GaN, the impurity-induced Fr\"ohlich mechanism becomes dominant. In the latter case, the observation of a relatively narrow line at the longitudinal-optical phonon frequency is consistent with the presence of a high-density electron gas.

30 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202340
202290
2021132
2020122
2019114
2018112