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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 paper, the authors discuss the implications of atomic disorder on ground-state properties of Fe2TiSn, in particular with respect to the role of the Kondo interaction.
Abstract: Recent electrical transport, specific heat and magnetic measurements indicated that the Heusler-type Fe2TiSn alloy could be a candidate for a 3d heavy-fermion system with a quasi-particle effective mass of ~40 times the free electron mass. Ab initio electronic structure calculations yield a nonmagnetic ground state with a pseudogap and a very small number of the density of states at the Fermi level. However, the atomic disorder strongly influences the magnetic and transport properties of Fe2TiSn samples. In contrast to the thermodynamical properties of Fe2TiSn, the infrared studies do not support the notion that the Kondo interaction plays a dominant role in this alloy and rather support the interband transition across a pseudogap responsible for the mass enhancement. The many-body calculations, however, have shown that the narrow d band resulting from Fe/Ti site exchange (i.e. Fe impurity atoms) can be responsible for the unusual temperature dependences of the physical properties of the Fe2TiSn alloy. In this review paper we discuss the implications of our findings for the ground-state properties of Fe2TiSn, in particular with respect to the role of atomic disorder.

36 citations

Journal ArticleDOI
TL;DR: The relation between excitons and plasmons in insulators is studied in this paper, where it is shown that exciton and plasmon solution of dispersion relation is expected on the higher energy side of M 3 − van Hove singularity provided the mean value of imaginary part of the dielectric constant exceeds some critical value below this energy and is small above this energy.
Abstract: The relation between excitons and “plasmons” in insulators is studied, and it is shown that both excitons and “plasmons” may be obtained in the singlet longitudinal states. When the energy of interband transition is nearly equal to the free electron plasmon energy \(\hbar\omega_{p}\), the energy and the angular dispersion of “plasmon” loss peaks are closely related to the structure of the pair band. In this case the “plasmon” solution of the dispersion relation is expected on the higher energy side of M 3 -(or M 2 -) van Hove singularity provided the mean value of imaginary part of the dielectric constant exceeds some critical value below this energy and is small above this energy. Recent experimental data of energy loss spectra on alkali-halides are analyzed making use of the optical data and the results of band structure calculations.

36 citations

Journal ArticleDOI
TL;DR: The experiment shows the essential role of the density of background material for allowing propagation of fast electrons, the importance of the ionization phase which produces free electrons available for the return current, and the effect of electrostatic fields on fast-electron propagation.
Abstract: We study the propagation of fast electrons in a gas at different densities. A large relativistic electron current is produced by focusing a short-pulse ultrahigh-intensity laser on a metallic target. It then propagates in a gas jet placed behind the foil. Shadowgraphy in the gas shows an electron cloud moving at sub-relativistic average velocities. The experiment shows (i) the essential role of the density of background material for allowing propagation of fast electrons, (ii) the importance of the ionization phase which produces free electrons available for the return current, and (iii) the effect of electrostatic fields on fast-electron propagation.

35 citations

Journal ArticleDOI
TL;DR: In this article, the electromagnetic generation of pure shear and quasicompressional sound waves in metals for propagation, respectively, parallel to and perpendicular to a static magnetic field, is investigated for a wide temperature range.
Abstract: The electromagnetic generation of pure shear and quasicompressional sound waves in metals for propagation, respectively, parallel to and perpendicular to a static magnetic field is investigated for a wide temperature range. Using a semiclassical model of a free electron gas moving against a positive ion background carrying the sound wave, the magnitude of the ionic displacements in the helicon geometry is calculated, together with the propagation constants. In the long‐wavelength limit, the excited mode that propagates differs only slightly from a normal acoustic shear mode. Satisfactory agreement is obtained when these calculations are compared with our experimental results at room temperature, 77° and 4.2°K in static magnetic fields of up to 100 kG.

35 citations

Journal ArticleDOI
TL;DR: A spin-polarizing electron beam splitter is described that relies on an arrangement of linearly polarized laser waves of nonrelativistic intensity that exerts the same effect on free electrons as an ordinary Stern-Gerlach magnet does on atoms.
Abstract: A spin-polarizing electron beam splitter is described that relies on an arrangement of linearly polarized laser waves of nonrelativistic intensity. An incident electron beam is first coherently scattered off a bichromatic laser field, splitting the beam into two portions, with electron spin and momentum being entangled. Afterwards, the partial beams are coherently superposed in an interferometric setup formed by standing laser waves. As a result, the outgoing electron beam is separated into its spin components along the laser magnetic field, which is shown by both analytical and numerical solutions of Pauli's equation. The proposed laser field configuration thus exerts the same effect on free electrons as an ordinary Stern-Gerlach magnet does on atoms.

35 citations


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