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Showing papers on "Plasmon published in 1977"


Journal ArticleDOI
TL;DR: In this paper, the two-dimensional plasmon of an inversion layer of (100) $p$-type Si was observed at a fixed wave vector as a function of electron density.
Abstract: The two-dimensional plasmon of an $n$ inversion layer of (100) $p$-type Si is observed at a fixed wave vector as a function of electron density. The position, width, and strength of the resonance agree with existing theory at electron densities \ensuremath{\gtrsim}${10}^{12}$/${\mathrm{cm}}^{2}$. At lower densities, the resonance position is below the predicted value, implying a substantial increase in the electron mass.

515 citations




Journal ArticleDOI
TL;DR: In this paper, the influence of a magnetic field on the behavior of the two-dimensional plasmon is studied in the n-inversion layer of p-type silicon at fixed wavevector as a function of electron density and magnetic field.

81 citations



Journal ArticleDOI
TL;DR: In this paper, a theoretical study of optical surface plasmon modes of metal spheres is made within the framework of a free-electron spatially dispersive dielectric function model which includes retardation effects.
Abstract: A theoretical study of optical surface plasmon modes of metal spheres is made within the framework of a free-electron spatially dispersive dielectric function model which includes retardation effects. Dispersion equations for homogeneous and inhomogeneous spheres are derived for the lth spherical harmonic. The radiative properties of the modes are investigated as a function of l and surface structure which is included by means of a double step-function profile. The real part of the frequency has the same magnitude, and trend with sphere radius, as the current experimental results.

66 citations


Journal ArticleDOI
TL;DR: In this article, the wavevector and frequency-dependent dielectric function of the charge carriers of n-GaAs has been studied using coupled plasmon-LO phonons.

50 citations


Journal ArticleDOI
U. Kreibig1
TL;DR: In this paper, size effects have been studied in Au particles of various sizes (102 to 105 atoms/particle), which were prepared in a glass matrix and showed that the spherical surface plasmon band is broadened and the imaginary part of the dielectric constant of the particle material increases.
Abstract: Size effects have been studied in Au particles of various sizes (102 to 105 atoms/particle), which were prepared in a glass matrix. Absorption measurements at 300 K and 1.5 K in the spectral region from 0.5 to 4.2 eV revealed three effects, when the particle size was reduced : (i) The spherical surface plasmon band is broadened ; the imaginary part of the dielectric constant of the particle material increases. (ii) The temperature dependence of the plasmon band goes to zero. (iii) The interband transition threshold is shifted to lower energies and the slope of the edge is diminished. Effects (i) and (ii) can be explained by assuming discrete electron energy levels, effect (iii) points to lattice parameter changes and/or an increase of indirect transitions.

48 citations


Journal ArticleDOI
TL;DR: In this article, the frequencies of the plasmons of small metal spheres are calculated using hydrodynamic theory and the effects of spatial dispersion and surface diffuseness, which are usually neglected, are included in the derivation.

47 citations


Journal ArticleDOI
TL;DR: In this article, the authors investigated the plasmon loss structures produced by the elastic electrons from the Si 2p and Al 2p core levels for different kinetic energies at the elastic electron.
Abstract: Photoelectron spectra of Al and Si have been excited by monochromatized synchrotron radiation at different photon energies. The plasmon loss structures produced by the elastic electrons from the Si 2p and Al 2p core levels have been investigated for different kinetic energies at the elastic electrons. Variation of the plasmon loss intensities for electron kinetic energies of 30–330 eV explains earlier reported absence of plasmon structure in uv photoelectron spectroscopy. The results also indicate that a model of extrinsic bulk plasmon excitation developed by Mahan and modified to account for surface effects could explain the observed threshold behavior of bulk plasmon intensity at low electron kinetic energies.

46 citations


Journal ArticleDOI
TL;DR: In this paper, the existence of strong absorptions of visible radiation by diffraction gratings is demonstrated using some simple considerations based on the Fresnel formula, and the theory is verified by comparison with numerical results from the previous integral formalism computer programs.
Abstract: Using some simple considerations based on the Fresnel formula, the existence of strong absorptions of visible radiation by diffraction gratings is demonstrated. The theory is verified by comparison with numerical results from the previous integral formalism computer programs. Finally, a very simple formula which predicts in a qualitative and quantitative manner the absorption of energy is derived. This theory, which can be applied to other anomalies, leads to the discovery of a surprising phenomenon: in the visible region and with the usual metallic gratings, it is possible to totally absorb an incident monochromatic wave.

Journal ArticleDOI
TL;DR: In this article, the RPA linear response theory is applied to the semi-infinite electron gas, in particular the infinite barrier model, in terms of the normal mode charge density fluctuations of the system.
Abstract: The RPA linear response theory as applied to the semi-infinite electron gas, in particular the infinite barrier model, is discussed in terms of the normal mode charge density fluctuations of the system. The normal modes separate into a discrete, surface mode with an electric field extending outside the solid and a continuum of bulk modes with no such fields. The surface mode, which corresponds to the undamped surface plasmon in the longwavelength limit, is examined at wave vectors up to the plasmon cut-off where it merges with the bulk modes. The bulk modes are also affected by the surface and we have calculated their phase shifts as a function of x, the wave vector perpendicular to the surface. In terms of these phase shifts we then discuss the change in the number of bulk modes when a surface is created; about 1/4 of a bulk mode is removed over an interval close to x=0 in addition to another 1/4 removed discretely at x=0. The surface exchange-correlation energy can be split into the change in the zero-point energy of the plasmons and the contribution from the screened electron-hole pair excitations, and we discuss the contribution in terms of zero-point energy of the surface plasmon and the change in the number of bulk modes.


Journal ArticleDOI
TL;DR: The plasmon-satellite structure observed in core-level photoemission spectra arises from so-called intrinsic or extrinsic plasmo as discussed by the authors, which is unknown.

Book ChapterDOI
01 Jan 1977
TL;DR: In this article, the experimental results are interpreted in terms of a theory of the dynamical conductivity, based on the equivalence of energy loss and Joule heat, and conditions under which the free electron contribution can be separated from that of the phonons and valence electrons.
Abstract: Optical and magnetooptical measurements on semiconductors, particularly in the submillimeterrange, are strongly affected by the free electrons. From the experimental spectra it is possible to deduce a dielectric function. Conditions are discussed under which the free electron contribution can be separated from that of the phonons and the valence electrons. The experimental results are interpreted in terms of a theory of the dynamical conductivity, based on the equivalence of “energy loss” and Joule heat. Within the RPA screening and plasmon effects are taken into account. As scattering centers we consider ionized impurities, vacancies, precipitations, dislocations and phonons. The effect of external magnetic fields is discussed.

Journal ArticleDOI
TL;DR: In this article, the plasmon structure of core lines in Be, Na, Mg, and Al metal has been analyzed, and it is shown that in each case extrinsic and intrinsic plasmons are present and that the probability of intrinsic plasmor creation is proportional to b n, where b is the creation rate for a single plasmon.

Journal ArticleDOI
TL;DR: In this paper, an electric field is applied normal to the surface of a metal crystal with force vector directed outwards, and electron-surface-plasmon scattering is dominated by trajectories with closest approach distance.
Abstract: Incident electrons follow a parabolic trajectory when an electric field is applied normal to the surface of a metal crystal with force vector directed outwards. Under appropriate conditions touching trajectories may be neglected, and electron--surface-plasmon scattering is dominated by trajectories with closest approach distance. Experimental results are presented for Mo indicating that only the 1.3-eV molybdenum surface plasmon is excited. Application of this new technique to measurements such as surface-plasmon dispersion is outlined. (AIP)

Journal ArticleDOI
TL;DR: Sunjic and Sokcevic as discussed by the authors used synchrotron radiation to provide a variable photon source in the ultra-soft X-ray region, thus allowing these loss processes to be studied at photoelectron kinetic energies for which the mean free path of the electrons is minimal.

Journal ArticleDOI
TL;DR: In this paper, the role of surface scattering of electrons in dispersive conducting media is studied in a semiclassical approximation using a phenomenological specularity parameter p (0 ~ p ~ 1).
Abstract: 2014 For dispersive conducting media the role of surface scattering of electrons is studied in a semiclassical approximation using a phenomenological specularity parameter p (0 ~ p ~ 1). The problem of unphysical charge accumulation at the surface, which often appears in treatments in terms of p, is explicitly discussed and avoided. The P-mode surface plasmon dispersion relation in the quasistatic limit (c ~ oo) is obtained for arbitrary p and 03BA (propagation vector). This permits a study of the effect of surface scattering on surface plasmon damping and also of the different roles of the longitudinal and transverse dielectric functions. This is illustrated with an application in terms of simple interpolation formulae for the dielectric functions. LE JOURNAL DE PHYSIQUE TOME 38, JUILLET 1977,

Journal ArticleDOI
TL;DR: In this paper, the nearly free electron pseudopotential theory is used to calculate the k-dependent plasmon linewidth that results from the decay of plasmons via interband transitions.
Abstract: The nearly free electron pseudopotential theory is used to calculate thek-dependent plasmon linewidth that results from the decay of plasmons via interband transitions. The theory predicts the linewidth to be anisotropic in crystalline systems fork ≠ 0. Local field effects are included, but are found to give very small contribution. A detailed analysis of the behaviour of the linewidth of Al is given and very good agreement with recent experimental data is obtained.

Journal ArticleDOI
TL;DR: In this article, it was shown that the coherent coupling of radiation into metal-barrier-metal structures by surface plasmons, which reduces to the usual antenna coupling at low frequencies, can be efficient up to a frequency at least as high as the plasma resonance.
Abstract: It is shown that the coherent coupling of radiation into metal‐barrier‐metal structures by surface plasmons, which reduces to the usual antenna coupling at low frequencies, can be efficient up to a frequency at least as high as the plasma resonance.

Journal ArticleDOI
TL;DR: In this article, the 1s spectrum in beryllium metal and the plasmons accompanying it have been measured by the XPS method and it was shown that they are created with about equal probability by direct energy loss and by the conduction electron hole coupling.

Journal ArticleDOI
TL;DR: In this article, a non-local theory of the coupling between plasmons and longitudinal optical phonons is proposed to explain the characteristic features of the Raman spectra of gallium arsenide.
Abstract: Recent experimental results of Raman spectra in gallium a arsenide are analyzed on the basis of a non-local theory of the coupling between plasmons and longitudinal optical (LO) phonons A formula is derived which gives the efficiency for the Raman scattering by a coupled LO phonon-plasmon (LO-PL) mode in an absorptive medium The finiteness of the wave number of the scattering mode and the attenuation of light in the medium are explicitlv taken into account An analysis of the GaAs Raman spectra obtained recently Murase et at shows that the theory reproduces the experimental results fairly well It also explains the characteristic features of the spectra The integrated efficiency from the LO-PL mode in GaAs is estimated to be of the order of 10 -11


Journal ArticleDOI
TL;DR: The analysis of the infrared reflectivity spectrum of partially reduced rutile TiO1.96 reveals a plasmon-LO phonon coupling as mentioned in this paper, and the frequency and life times of pure-phonon and PLPs were determined by fit with an appropriate model using the factorized form of the dielectric function for the phonon modes added to a plasmons contribution also derived from the factorised form.

Journal ArticleDOI
TL;DR: In this paper, a multi-subband system in an inversion layer on III-V semiconductors is considered, where the carriers of each subband oscillate out of phase.
Abstract: In a multi-subband system in an inversion layer on III-V semiconductors, there can be an acoustic plasmon in which carriers of each subband oscillate out of phase. The dispersion relation and the L...

Journal ArticleDOI
TL;DR: In this paper, the authors considered the parametric decay of an electromagnetic wave into two electron plasma waves in an inhomogeneous plasma and showed that the threshold for absolute instability decreases as the angle of incidence of the electromagnetic wave relative to the density gradient approaches 90°.
Abstract: The parametric decay of an electromagnetic wave into two electron plasma waves in an inhomogeneous plasma is considered. The electromagnetic wave is obliquely incident on the density gradient. The resulting analysis shows that the threshold for absolute instability decreases as the angle of incidence of the electromagnetic wave relative to the density gradient aproaches 90°. The limitations of this analysis and its importance to laser fusion are discussed.

Journal ArticleDOI
TL;DR: In this article, the plasmon energy losses associated with Al, Zn, and Mg Auger peaks are different, and the energy losses vary with heat treatment of the alloy.
Abstract: Grain‐boundary surfaces of Al‐Zn‐Mg alloys have been studied with Auger electron spectroscopy. Particular emphasis was given to plasmon loss satellites in the Auger spectrum. It is found that the plasmon energy losses associated with Al, Zn, and Mg Auger peaks are different, and the energy losses vary with heat treatment of the alloy. These variations provide information on chemical composition and nonhomogeneities in an alloy, such as precipitation and segregation. It is shown that, at the grain boundary of aged specimens of the Al alloy, the Zn atoms are all in the form of MgZn2 precipitates, but only about 40% of the total Mg is in the precipitates. The other 60% is situated outside of the precipitates.


Journal ArticleDOI
TL;DR: In this paper, the interaction between two-dimensional interface plasmons and longitudinal optical phonons in multilayer structures is analyzed and the dispersion relations for the mixed modes are obtained for periodic boundary conditions in the direction normal to the layer planes.