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Wyszukujesz frazę "72.10.-d" wg kryterium: Temat


Tytuł:
Angular Distribution of Photoemission from Surfaces of Amorphous Solids
Autorzy:
Jabłoński, A.
Powiązania:
https://bibliotekanauki.pl/articles/1931731.pdf
Data publikacji:
1994-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
34.80.Bm
72.10.-d
79.60.-i
Opis:
As follows from the formalism of X-ray photoelectron spectroscopy, knowledge of the angular distribution of photoemission is crucial for certain applications of quantitative X-ray photoelectron spectroscopy analysis. In the present work, the experimental data on the relative angular distribution of photoemission from solid materials are reviewed and compared with theoretical predictions. Noticeable discrepancies are usually observed. It has been proved that major part of the observed discrepancies can be ascribed to elastic photoelectron scattering. The commonly used formalism, where the elastic collisions are neglected, may be of insufficient reliability for certain solids, or in certain experimental geometries. This formalism can be easily extended to account for elastic photoelectron collisions by introducing two correction factors, Q$\text{}_{X}$ and β$\text{}_{eff}$. The second parameter, called the effective asymmetry parameter, describes the observed decrease in anisotropy of photoemission. Determination of the correction factors requires a reliable theory describing elastic electron scattering in the solid. A need arises for accurate differential and total elastic electron scattering cross-sections pertinent to kinetic energies of considered photoelectrons or the Auger electrons. The increasingly important role of electron transport in surface analysis has stimulated an effort to construct a complete database containing the differential and total atomic elastic scattering cross-sections.
Źródło:
Acta Physica Polonica A; 1994, 86, 5; 787-798
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Auger Recombination in Low-Dimensional PbSnTe Structures
Autorzy:
Mocker, M.
Lemke, F.
Powiązania:
https://bibliotekanauki.pl/articles/1879926.pdf
Data publikacji:
1991-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.10.-d
Opis:
How is the efficiency of Auger recombination in PbSnTe structures influenced by the reduction of dimensionality? Two points are investigated, the variation of matrix elements and of activation energies, respectively. It is shown that the latter one gives the more decisive effect. This effect is strongly anisotropic. Thus, {100}-planes or [100]-directions are favoured to yield large Auger lifetimes for Q2D or Q1D structures, respectively.
Źródło:
Acta Physica Polonica A; 1991, 79, 2-3; 207-212
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Band Structure and Magnetic Properties of DO$\text{}_{3}$-Type Fe$\text{}_{3-x}$V$\text{}_{x}$Al Alloys. Super-Cell Approach
Autorzy:
Deniszczyk, J.
Borgieł, W.
Powiązania:
https://bibliotekanauki.pl/articles/2014414.pdf
Data publikacji:
2000-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.20.Eh
71.20.-b
72.15.-v
72.10.-d
Opis:
The electronic structure of Fe$\text{}_{3-x}$V$\text{}_{x}$Al alloys was calculated using the super-cell methodology of alloy modeling. The concentration range of x=0.0÷1.0 was investigated. For a concentration of x=0.0625 the energy based analysis reveals that vanadium prefers to replace the Fe atom at sites with the octahedral coordination. It was found that the iron atoms coordinated by the eight nearest-neighbor Fe atoms preserve their high magnetic moment up to a concentration of x=0.9375 even though the average total magnetic moment goes to zero. The relatively high (≃ -1.0μB) negative magnetic moment of V remains constant up to x≃ 0.5. In the concentration range of x=0.75÷0.9375 the gap at ε$\text{}_{F}$ of the minority density of states is observed while the majority density of states displays a sharp peak structure at the Fermi energy. This feature suggests the heavy-fermion behavior of the Fe$\text{}_{2}$VAl compound.
Źródło:
Acta Physica Polonica A; 2000, 98, 5; 551-554
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Charge Carrier Transport in Quantum Cascade Lasers in Strong Magnetic Field
Autorzy:
Radovanović, J.
Milanović, V.
Indjin, D.
Ikonić, Z.
Harrison, P.
Powiązania:
https://bibliotekanauki.pl/articles/1505456.pdf
Data publikacji:
2011-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.10.-d
73.21.Fg
Opis:
We have developed a comprehensive rate equations based model for calculating the optical gain in the active region of a quantum cascade laser in magnetic field perpendicular to the structure layers, which takes into account all the relevant scattering channels. The model is applied to gain-optimized quantum cascade laser active region, obtained by a systematic optimization procedure based on the use of genetic algorithm, which we have previously set up for designing novel structures and improving performance of existing ones. It has proven to be very efficient in generating optimal structures which emit radiation at specified wavelengths corresponding to absorption fingerprints of particular harmful pollutants found in the atmosphere. We also illustrate another interesting prospective application of quantum cascade laser-type structures: the design of metamaterials with tunable complex permittivity, based on amplification via intersubband transitions. In this case, the role of the magnetic field is to assist the attainment of sufficient optical gain (population inversion), necessary to effectively manipulate the permittivity and fulfill the conditions for negative refraction (left-handedness).
Źródło:
Acta Physica Polonica A; 2011, 119, 2; 99-102
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Correlation Effects and Spin Dependent Transport in Carbon Nanostructures
Autorzy:
Lipiński, S.
Krychowski, D.
Powiązania:
https://bibliotekanauki.pl/articles/1201833.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.10.Fk
73.63.Fg
73.63.Kv
85.75.-d
Opis:
The impact of symmetry breaking perturbations on the spin dependent transport through carbon nanotube quantum dots in the Kondo regime is discussed. The proposals of spin filter, spin valve and spin battery are presented.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 190-193
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dielectric and Ac Conductivity Studies of Mn-Doped $Na_{1.86}Li_{0.10}K_{0.04}Ti_3O_7$ Ceramics
Autorzy:
Singh, R.
Shripal, S.
Powiązania:
https://bibliotekanauki.pl/articles/1206481.pdf
Data publikacji:
2014-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.10.Bg
72.20.Ee
72.60.+g
77.22.-d
77.22.Gm
77.22.Jp
Opis:
Dielectric-spectroscopic and ac conductivity studies on 0.01 and 1.0 molar percentage manganese doped layered $Na_{1.86}Li_{0.10}K_{0.04}Ti_3O_7$ ceramics have been reported. The dependence of loss tangent (tan δ) and relative permittivity ($ε_{r}$) on temperature in the range 350-775 K and on frequency in the range 10 kHz-1 MHz have been undertaken. The losses are the characteristics of dipole mechanism, electrical conduction and space charge polarization. The obtained conductivity plots between log($σ_{ac}T$) versus 1000/T have been divided into four regions namely region I, II, III, and IV. The mechanism of conduction in region I is acknowledged to electronic hopping conduction. The less frequency and more temperature dependent region II is ascribed as a mixed mechanism "associated interlayer ionic conduction, electron hopping, and alkali ion hopping conduction". The unassociated interlayer ionic conduction along with alkali ion hopping conduction mechanisms are contributing to the transport process in the mid temperature region III. The mechanism of conduction in the highest temperature region IV may be recognized as the modified interlayer ionic conduction. The conductivity versus frequency curves lead to conclude that the electronic hopping conduction diminishes with the rise of temperature.
Źródło:
Acta Physica Polonica A; 2014, 125, 1; 67-72
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electrical Conductivity for the Strongly Correlated and Hybridized Hubbard Band
Autorzy:
Kosimow, R.
Borgieł, W.
Deniszczyk, J.
Powiązania:
https://bibliotekanauki.pl/articles/2013654.pdf
Data publikacji:
2000-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.10.Fd
71.27.+a
72.10.-d
72.15.-v
Opis:
The magnetic and electrical transport properties of strongly correlated Hubbard band (f-band) hybridizing with the non-correlated conduction band (c-band) was studied. The many-body model Hamiltonian was treated within the modified alloy analogy scheme and the resulting one-body problem was solved with the use of coherent potential approximation. Within the Kubo-Greenwood formalism the dc electrical conductivity for bcc magnetic system was calculated and its variation with temperature and number of electrons was examined for different values of the Coulomb and hybridization (V) coupling constants. We found that the effect of strong correlations and hybridization on the conductivity is similar to that produced by the scattering due to the s-f interaction (spin disorder resistivity).
Źródło:
Acta Physica Polonica A; 2000, 97, 5; 799-802
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electromagnetic Properties of Mesoscopic Cylinder
Autorzy:
Zipper, E.
Stebelski, M.
Lisowski, M.
Powiązania:
https://bibliotekanauki.pl/articles/1968457.pdf
Data publikacji:
1997-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.30.+h
72.10.-d
Opis:
The electromagnetic response of a mesoscopic cylinder made of a normal metal or a semiconductor is studied. The relation between the induced current J(q,w) and the electric field E(q,w) is derived. It is shown that the kernel K(q,w) which determines the properties of the system has a finite limit which implies infinite conductivity. The mesoscopic cylinder by virtue of its topology and small dimensions can support a persistent current. If the coherence of currents from different channels is strong enough a novel effect - the self-sustaining current can be obtained. We show that a mesoscopic multichannel system exhibits some features which bear resemblance to the superconductor.
Źródło:
Acta Physica Polonica A; 1997, 92, 5; 1087-1091
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electronic Structure and Electron-Transport Properties of (Gd$\text{}_{1-x}$Y$\text{}_{x}$)$\text{}_{2}$In Compounds
Autorzy:
Borgieł, W.
Deniszczyk, J.
Powiązania:
https://bibliotekanauki.pl/articles/2013400.pdf
Data publikacji:
2000-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.10.-d
72.15.-v
71.20.Eh
71.20.-b
Opis:
Based on the electronic structure of the ferromagnetic Gd$\text{}_{2}$In and (Gd$\text{}_{0.5}$ Y$\text{}_{0.5}$)$\text{}_{2}$In compounds the high-temperature magnetic part of the electrical resistivity of (Gd$\text{}_{1-x}$Y$\text{}_{x}$)$\text{}_{2}$In as a function of Y concentration was calculated and analyzed. The main interaction which causes the finite magnetic part of the conductivity was assumed in a form of stochastically distributed in space s-f interaction. The calculated resistivity of (Gd$\text{}_{1-x}$Y$\text{}_{x}$)$\text{}_{2}$In alloys qualitatively reproduces the experimental data.
Źródło:
Acta Physica Polonica A; 2000, 97, 5; 783-786
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Enhancement of Electron Mobility and Photoconductivity in Quantum Well $In_{0.52}Al_{0.48}As//In_{0.53}Ga_{0.47}As//In_{0.52}Al_{0.48}As$ οn InP Substrate
Autorzy:
Kulbachinskii, V.
Lunin, R.
Yuzeeva, N.
Galiev, G.
Vasilievskii, I.
Klimov, E.
Powiązania:
https://bibliotekanauki.pl/articles/1399881.pdf
Data publikacji:
2013-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.10.-d
73.21.Fg
73.63.Hs
Opis:
Isomorphic $In_{0.52}Al_{0.48}As//In_{0.53}Ga_{0.47}As//In_{0.52}Al_{0.48}As$ quantum well structure on InP substrate were grown by molecular beam epitaxy. We investigated the electron transport properties and mobility enhancement in the structures by changing of doping level, the width d of quantum well $In_{0.53}Ga_{0.47}As$ or by illumination using light with λ = 668 nm. Persistent photoconductivity was observed in all samples due to spatial separation of carriers. We used the Shubnikov-de Haas effect to analyze subband electron concentration and mobility. The maximal mobility was observed for quantum well width d = 16 nm.
Źródło:
Acta Physica Polonica A; 2013, 123, 2; 345-348
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Excess Conductivity of Y$\text{}_{0.95}$Pr$\text{}_{0.05}$Ba$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{7-x}$ Single Crystals
Autorzy:
Vovk, R. V.
Obolenskii, M. A.
Bondarenko, A. V.
Goulatis, I. L.
Chroneos, A.
Powiązania:
https://bibliotekanauki.pl/articles/2047236.pdf
Data publikacji:
2007-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.20.Eh
72.10.-d
74.40.+k
74.72.-h
Opis:
In this work we investigate the conductivity in the basis plane of YBa$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{7-x}$ and Y$\text{}_{1-z}$Pr$\text{}_{z}$Ba$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{7-x}$ single crystals with a system of one-direction twin boundaries. The Pr dopants behave as efficient scattering centers of normal and fluctuating carriers. For this a slight doping with praseodymium (till z≈0.05) results in a significant narrowing of the temperature interval in which the pseudo-gap regime is realized in the ab-plane of YBaCuO single crystals.
Źródło:
Acta Physica Polonica A; 2007, 111, 1; 129-133
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Impurity Self-Screening
Autorzy:
Wilamowski, Z.
Przybylińska, H.
Powiązania:
https://bibliotekanauki.pl/articles/1929774.pdf
Data publikacji:
1993-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.45.-d
72.10.Fk
Opis:
In a mixed valence impurity system the distribution of impurity charges can be adjusted to minimize the Coulomb energy of inter-impurity interactions. In this paper we discuss the possibility of extending the methods of analytical evaluation of the pair correlation function for classical liquids to apply to a system with a built-in disorder, where the occupation probability is governed by the Fermi-Dirac statistics.
Źródło:
Acta Physica Polonica A; 1993, 84, 4; 832-834
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Chemical Composition of Liquid Phase and Growth Process on Physical Properties of $Bi_2Se_3,$ $Bi_2Te_3$ and $Bi_2Te_2Se$ Compounds
Autorzy:
Hruban, A.
Materna, A.
Dalecki, W.
Strzelecka, G.
Piersa, M.
Jurkiewicz-Wegner, E.
Diduszko, R.
Romaniec, M.
Orłowski, W.
Powiązania:
https://bibliotekanauki.pl/articles/1492965.pdf
Data publikacji:
2011-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.55.-i
72.10.-d
72.15.-v
72.20.-I
73.20.-r
Opis:
We studied synthesis and crystal growth of $Bi_2Te_3,$ $Bi_2Se_3$ and $Bi_2Te_2Se$ compounds by means of vertical Bridgman method. Crystals were grown from stoichiometric melts and under different molar ratio of Bi:Te, Bi:Se or Bi:Te:Se. The obtained crystals were characterized by X-ray diffraction analysis, energy dispersive X-ray spectroscopy, scanning electron microscopy, atomic force microscopy, and the Hall effect measurements. Some of the samples demonstrated insulating bulk behavior, by means of resistivity versus temperature measurements.
Źródło:
Acta Physica Polonica A; 2011, 120, 5; 950-953
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Inter-Landau Level Scattering Processes in Magnetic Field Assisted THz Quantum Cascade Laser
Autorzy:
Radovanović, J.
Daničić, A.
Milanović, V.
Indjin, D.
Ikonic, Z.
Powiązania:
https://bibliotekanauki.pl/articles/1503186.pdf
Data publikacji:
2011-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.10.-d
73.21.Fg
Opis:
We present a detailed analysis of GaAs/AlGaAs terahertz quantum cascade laser in the presence of an intense external magnetic field. One of the objectives in further development of THz quantum cascade laser is the realization of structures operating at higher temperatures. This is difficult to obtain as the operating photon emission energy is smaller than the longitudinal-optical phonon energy in the semiconductor material. With increased temperature, electrons in the upper radiative state gain sufficient in-plane energy to emit an longitudinal-optical phonon, which represents a non-radiative scattering and reduces the optical gain. By applying strong magnetic field, two-dimensional continuous energy subbands become split into series of discrete Landau levels, and at particular values of B it is possible to quench these non-radiative channels. Numerical simulations are performed on two-well design quantum cascade laser operating at 4.6 THz, implemented in GaAs/$Al_{0.15}Ga_{0.85}As$, and the magnetic field is perpendicular to the epitaxial layers. Strong oscillations of carrier lifetimes for the upper state of the laser transition, as a function of magnetic field are observed, which can be attributed to interface roughness scattering and longitudinal-optical phonon scattering between Landau levels.
Źródło:
Acta Physica Polonica A; 2011, 120, 2; 227-230
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Intervalley Scattering and the Role of Indirect Band Gap AlAs Barriers: Application to GaAs/AlGaAs Quantum Cascade Lasers
Autorzy:
Mc Tavish, J.
Ikonić, Z.
Indjin, D.
Harrison, P.
Powiązania:
https://bibliotekanauki.pl/articles/1813212.pdf
Data publikacji:
2008-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.10.-d
73.21.Fg
73.63.Hs
Opis:
We report on the results of our simulations of Γ-X scattering in GaAs/AlGaAs heterostructures, discussing the importance of the mole fraction, doping density, and lattice and electron temperature in determining the scattering rates. We consider three systems, a single quantum well (for the investigation of Γ-X scattering), a double quantum well (to compare the Γ-X-G and Γ-Γ scattering rates), and an example of a GaAs/AlGaAs mid-infrared quantum cascade laser. Our simulations suggest that Γ-X scattering can be significant at room temperature but falls off rapidly at lower temperatures. One important factor determining the scattering rate is found to be the energy difference between the Γ- and X-states.
Źródło:
Acta Physica Polonica A; 2008, 113, 3; 891-902
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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