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.

Numerical simulations of the polariton kinetic energy distribution in GaAs quantum-well microcavity structures

Abstract: Recent experiments have shown that polaritons in microcavities behave like a Bose-Einstein condensate above a critical density threshold and at low temperature. The polaritons are not in full equilibrium, however, due to particle decay and streaming in of generated particles from high-energy states. In this paper we present a full simulation of the thermalization of polariton and exciton populations, including polariton-polariton and exciton-exciton scattering, phonon emission and absorption, and polariton scattering with free electrons. We find that we can obtain good fits over a wide range of polariton densities. The fits imply that the enhancement of the polariton-polariton scattering due to Bose-Einstein statistics does indeed play the major role in the particles piling up in low-energy states, which is the precursor to Bose condensation. Our fits also indicate that at low density, scattering of the polaritons with free electrons plays a more important role than polaritonphonon scattering.

Revisiting the origin of satellites in core-level photoemission of transparent conducting oxides: The case of n -doped SnO2

Abstract: The longstanding problem of interpretation of satellite structures in core-level photoemission spectra of metallic systems with a low density of conduction electrons is addressed using the specific example of Sb-doped SnO2. Comparison of ab initio many-body calculations with experimental hard x-ray photoemission spectra of the Sn 4d states shows that strong satellites are produced by coupling of the Sn core hole to the plasma oscillations of the free electrons introduced by doping. Within the same theoretical framework, spectral changes of the valence band spectra are also related to dynamical screening effects. These results demonstrate that, for the interpretation of electron correlation features in the core-level photoelectron spectra of such narrow-band materials, going beyond the homogeneous electron gas electron-plasmon coupling model is essential.

Resonant reflectors for free electron masers

Abstract: A new type of a waveguide reflector is discussed. Its operating principle is based on the effect of resonant reflection of a wave from a cavity when there is coupling between the wave and an eigenmode of the cavity. The resonant reflectors are very attractive for the use in microwave systems of free electron masers due to their high reflection coefficients and narrow frequency bands at comparatively short lengths. Results of calculations and measurements of some resonant reflectors and a microwave system for KA-band cyclotron autoresonance masers are presented.

Interpretation of the Optical Properties of Metal Surfaces

Abstract: The surface optical properties of the metals Ag, Au, Cu, Pt, Ir, and Ni in the infrared are shown to obey a simple generalized form of the Drude formula for the free electron theory, but involving two types of free electrons. If the surface optical constants are not anomalous, this procedure may be interpreted as a source of information on the density and relaxation times of free electrons in different overlapping energy bands. The evidence for and against anomalous surface optical constants is reviewed and it is concluded that the optical constants in the interior are the same as those measured on the surface.