Informacja

Drogi użytkowniku, aplikacja do prawidłowego działania wymaga obsługi JavaScript. Proszę włącz obsługę JavaScript w Twojej przeglądarce.

English (EN)·Polski (PL)·Yкраїнський (UK)
Przejdź do strony domowej biblioteki Centralna Biblioteka Wojskowa Link otwiera się w nowym oknie Logo biblioteki Prolib Integro - strona głównaCentralna Biblioteka Wojskowa

Wyszukujesz frazę "Phonons" wg kryterium: Wszystkie pola

  Lista filtrów
Wyrównaj
Wyświetlanie 1-15 z 24
Tytuł:
Raman Scattering from Acoustic Phonons Confined in Spherical Nanoparticles
Autorzy:
Kostić, R.
Powiązania:
https://bibliotekanauki.pl/articles/1807815.pdf
Data publikacji:
2009-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.46.Df
63.22.-m
Opis:
Low-frequency Raman scattering from small spherical particles is analyzed. Frequencies of vibrational modes are calculated in elastic continuum approximation, which considers one nanoparticle as homogeneous elastic sphere. Parameters of this model are transverse $(v_T)$ and longitudinal $(v_L)$ sound velocities of material, i.e. elastic properties of bulk material. Frequencies of vibrational modes are scaled as function of mentioned bulk parameters for symmetric l=0 and quadrupolar l=2 spheroidal modes, in the case of stress-free boundary conditions. Calculated values are compared with the low-frequency Raman experimental results from literature (Ge, Si, CdS, CdSe, $CeO_2$, ...). These calculated relations can be practically used to examine nanoparticles of any bulk material. We presented also a procedure how to establish $v_L$ and $v_T$ of material from low-frequency Raman spectra and dimension d of particles.
Źródło:
Acta Physica Polonica A; 2009, 116, 1; 62-64
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stimulated Raman Scattering of Nonclassical Light by Squeezed Phonons
Autorzy:
Peřina, J.
Kárská, M.
Křepelka, J.
Powiązania:
https://bibliotekanauki.pl/articles/1887739.pdf
Data publikacji:
1991-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.50
Opis:
Quantum statistical properties are derived for stimulated Raman scattering by squeezed phonons including squeezing of vacuum fluctuations in radiation modes and sub-Poisson photon behaviour. Initial radiation can be in squeezed thermalized and/or sub-Poisson states, phonon system can also be squeezed. In particular, effects of initial phase conditions, losses, initial nonclassical behaviour and phonon squeezing are demonstrated in terms of reduced factorial moments up to the fifth order in combined photon-photon and photon-phonon modes. Also photon number distribution, quadrature variances and principał squeeze parameters are shown.
Źródło:
Acta Physica Polonica A; 1991, 79, 6; 817-828
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Resonant Phonons in Adsorbed Slabs
Autorzy:
Dobrzynski, L.
Akjouj, A.
Syla, B.
Djafari-Rouhani, B.
Powiązania:
https://bibliotekanauki.pl/articles/1892256.pdf
Data publikacji:
1992-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
68.60.-p
Opis:
Resonant phonons, sometimes also called leaky waves, are phonons associated with a crystal defect, a surface, an adsorbed layer and whose frequencies fall inside the bulk crystal band. Such resonant phonons were studied experimentally and theoretically before for clean surfaces and for adsorbed monolayers. We present here a study of resonant phonons associated with the adsorption of a slab of L monolayers on a substrate. With the help of a simple atomic model, we obtained a closed form expression giving the variation of the transverse phonon density of states associated with the adsorption of the slab. An application which qualitatively simulates the adsorption of L monolayers of Ge on Si shows the existence of well-defined resonant phonons within the bulk acoustic band of the substrate.
Źródło:
Acta Physica Polonica A; 1992, 81, 1; 85-90
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Scattering of Excitons by Phonons in Quantum Wells
Autorzy:
Bardyszewski, W.
Prywata, M.
Powiązania:
https://bibliotekanauki.pl/articles/1947245.pdf
Data publikacji:
1996-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.20.Dx
71.38.+i
72.80.Ey
Opis:
A method to describe the effects of the exciton-optical phonon interaction is presented using the cumulant expansion approximation. The functional-integral technique of coherent phonon states is used in order to justify the commonly used model Hamiltonian and generate the proper perturbation series. The influence of the mutual electron-hole screening on the polaronic effects in quantum wells is analyzed.
Źródło:
Acta Physica Polonica A; 1996, 90, 4; 715-718
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Unified Approach to Interface and Confined Bulk Optical Phonons in Quantum Wells and Superlattices
Autorzy:
Röseler, J.
Suisky, D.
Powiązania:
https://bibliotekanauki.pl/articles/1924261.pdf
Data publikacji:
1992-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.20.Dx
Opis:
A unified description of confined optical LO, TO and interface phonons is given on the basis of vector "ghost" fields defined in the whole space. These fields are characterized by the relations for longitudinal and transversal fields. Real displacement fields are obtained by introducing confinement conditions. Interface charges and vortices appear due to this procedure.
Źródło:
Acta Physica Polonica A; 1992, 82, 5; 919-923
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Resonant Phonons in Adsorbates
Autorzy:
Dobrzynski, L.
Djafari Rouhani, B.
Zieliński, P.
Akjouj, A.
Sylla, B.
Oumghar, E.
Powiązania:
https://bibliotekanauki.pl/articles/1943987.pdf
Data publikacji:
1996-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
68.35.JS
68.45.-v
Opis:
After a brief review on surface phonons, we focus on resonant phonons in adsorbed thin layers. Such resonances may in general be understood within the substrate bulk band as thin layer modes shiften and broaden by the interaction with the substrate phonons. These resonant phonons appear as well-defined peaks in the phonon density of states. Their experimental study started recently by Helium atom scattering spectroscopy. This review will end by a prospective revue done mostly after the presentation of two unpublished results. First the slab resonant phonons may almost be confined in the surface slab even for frequencies falling within the bulk phonon band, if the surface slab is separated from the substrate by a buffer layer. The other prospective unpublished result deals with a model system in which the propagating phonons reach a space point from which they can continue to propagate through two different finite in space channels before reaching again a homogeneous uniform path. Such a system exhibits some frequencies for which the transmission factor vanishes. This phenomenon is related to the resonances associated with the finite additional path offered to the propagation of the phonons.
Źródło:
Acta Physica Polonica A; 1996, 89, 2; 139-144
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phonon-Induced Thermodynamic Properties of Ultra-narrow Wires
Autorzy:
Ilić, D.
Šetrajčić, J.
Jaćimovski, S.
Powiązania:
https://bibliotekanauki.pl/articles/1029824.pdf
Data publikacji:
2018-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
Phonons
ultra-narrow wire
the Green function
thermodynamics
specific heat
Opis:
In this paper, we investigated the influence of size effect on thermodynamic properties of ultra-narrow wires with a simple cubic lattice, by means of two-time dependent Green functions method, adjusted to confined crystalline structures. Poles of Green functions, which defining phonon spectra, are found by solving the secular equation. For different boundary parameters, this problem is presented graphically. The temperature behavior of ultra-narrow wire thermal capacitance is compared to that of bulk structures. It turned out that in low-temperature region thermal capacitance of the ultra-narrow wire is notably lower than in the corresponding bulk sample. How this fact reflects the thermal, conducting and superconducting properties of materials, is discussed in the conclusion.
Źródło:
Acta Physica Polonica A; 2018, 133, 1; 57-62
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of Phonons in HgCdMnTe Using Far-Infrared Reflectivity
Autorzy:
Dudziak, E.
Bożym, J.
Pruchnik, D.
Baran, J.
Powiązania:
https://bibliotekanauki.pl/articles/1929684.pdf
Data publikacji:
1993-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.30.Fs
71.45.Gm
Opis:
The first reflectivity spectra of Hg$\text{}_{1-x-y}$Cd$\text{}_{x}$Mn$\text{}_{y}$Te with 0.03 < x < 0.1 and 0 < y < 0.05 were measured in the spectral region 700-30 cm$\text{}^{-1}$ at 300 K and 90 K. The quaternary alloys measured show three mode behaviour. The experimental results are interpreted by using a classical dynamic dielectric function model.
Źródło:
Acta Physica Polonica A; 1993, 84, 3; 595-598
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hot Phonons in a Biased Two-Dimensional InGaAs Channel
Autorzy:
Aninkevičius, V.
Liberis, J.
Matulionis, A.
Matulionienė, I.
Powiązania:
https://bibliotekanauki.pl/articles/1818476.pdf
Data publikacji:
2005-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
63.20.Kr
72.20.Ht
Opis:
Experimental dependence of microwave noise temperature on supplied electric power is used to estimate hot-phonon number in a modulation-doped In_{0.52}Al_{0.48}As/In_{0.53}Ga_{0.47}As/In_{0.7} Ga_{0.3}As/In_{0.52}Al_{0.48}As two-dimensional electron gas channel (n_{2D}=2.3×10^{12} cm^{-2}). The nonequilibrium occupancy of the involved longitudinal optical phonon states exceeds the equilibrium one nearly twice at 2 kV/cm electric field. test
Źródło:
Acta Physica Polonica A; 2005, 107, 2; 304-309
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Transient Response of Electrons and Phonons in ZnTe Crystals
Autorzy:
Brazis, R.
Raguotis, R.
Powiązania:
https://bibliotekanauki.pl/articles/1813220.pdf
Data publikacji:
2008-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.10.Di
72.20.Ht
72.15.Lh
78.45.+h
Opis:
The response of electron and phonon ensemble to the switching on and off electric field E in n-type ZnTe crystals is simulated by Monte Carlo method. The results at T=10 K show significant accumulation of LO-phonons and the LO phonon band population inversion with respect to the LA band;the inversion is necessary for the stimulated transfer of LO-LA energy difference to photons. The maximum inversion is at E=7 kV/cm. At T=300 K no phonon band inversion but fast (sub-picosecond) drift velocity switching with ≈100 GHz repetition is feasible.
Źródło:
Acta Physica Polonica A; 2008, 113, 3; 933-936
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Observation of Second-Generation Nonequilibrium Phonons in Highly Photoexcited CdS Microcrystals
Autorzy:
Kurilc̆ik, G.
Strumskis, M.
Jurs̆ėnas, S.
Z̆ukauskas, A.
Powiązania:
https://bibliotekanauki.pl/articles/1952036.pdf
Data publikacji:
1996-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
63.20.Kr
78.47.+p
78.55.Et
Opis:
Luminescence kinetics of nonthermalized electron-hole plasma in highly excited CdS microcrystals embedded in glass was studied at T=295 K using two pump pulses technique. The observed carrier kinetics shows additional increase in the effective temperature during the pump pulse as a result of the prepump pulse. The increase is shown to be produced by a fusion of long-lived second-generation nonequilibrium phonons generated by the prepump pulse. The experimental results are in good agreement with a model of hot electron-hole plasma energy relaxation with a build-up of two generations of nonequilibrium phonons.
Źródło:
Acta Physica Polonica A; 1996, 90, 5; 875-878
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Acoustic Phonons on the Magnetic Anisotropy in GaMnAs Magnetic Semiconductors
Autorzy:
Jasiukiewicz, C.
Stagraczyński, S.
Lehmann, D.
Dugaev, V.
Berakdar, J.
Powiązania:
https://bibliotekanauki.pl/articles/1402566.pdf
Data publikacji:
2015-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
75.30.Gw
77.80.Fm
Opis:
We present a theoretical description of the influence of incoherent acoustic phonons on the magnetic anisotropy of magnetic semiconductors. Our theory is based on the six-band Kane model of the electron energy spectrum describing the valence band with k· p Hamiltonian including the hole-phonon interaction term. We include the effect of incoherent phonons through the hole self-energy in the six-band model, and assume a strong laser-pulse-induced flux of non-equilibrium acoustic phonons. The results of numerical calculations of magnetic anisotropy performed for (GaMn)(AsP) magnetic alloy semiconductors demonstrate the essential role of incoherent phonons.
Źródło:
Acta Physica Polonica A; 2015, 128, 2; 179-181
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Infrared active phonons and optical band gap in multiferroic GdMnO₃ studied by infrared and UV-visible spectroscopy
Autorzy:
Bukhari, S.
Ahmad, J.
Powiązania:
https://bibliotekanauki.pl/articles/1075504.pdf
Data publikacji:
2016-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
63.20.-e
78.20.-e
72.20.-i
73.20.Mf
Opis:
Optical properties of multiferroic GdMnO₃ synthesized by sol-gel method have been investigated by measuring the infrared reflectivity and UV-visible absorption spectra. The infrared reflectivity spectrum of polycrystalline GdMnO₃ in the frequency range 30-7500 cm^{-1} at room temperature contains several phonon modes. The resonant frequency of observed infrared active phonon modes is found comparable with theoretically predicted results. Mean Born effective charges are calculated and discussed in view of the origin of ferroelectricity in GdMnO₃. Three strong absorption peaks observed in the UV-visible spectrum are attributed to the Mn (3d)-electron transitions. The optical band gap ≈1.2 eV is estimated from UV-visible absorption spectrum using Tauc's relation. GdMnO₃ seems to behave like an indirect gap semiconductor.
Źródło:
Acta Physica Polonica A; 2016, 129, 1; 43-48
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Interplay between Correlated Electrons and Quantum Phonons in Charge-Ordered and Mott-Insulating Organic Compounds
Autorzy:
Yonemitsu, K.
Maeshima, N.
Tanaka, Y.
Powiązania:
https://bibliotekanauki.pl/articles/1490009.pdf
Data publikacji:
2012-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.20.Bh
71.30.+h
71.45.Lr
71.10.Fd
Opis:
At an early stage of the photoinduced transition from an insulator to a metal in quasi-two-dimensional organic conductors, a coherent motion of electrons is observed in a charge-ordered insulator, but not so far in a Mott insulator. The mechanisms of these different photoinduced charge dynamics are theoretically studied by numerical solutions to the time-dependent Schrödinger equation for exact many-electron-phonon wave functions on small clusters of model systems. We use two-dimensional three-quarter-filled extended Holstein-Hubbard models on anisotropic triangular lattices. For a charge-ordered insulator on a lattice simplified from the structure of $α-\text{(BEDT-TTF)}_2I_3$, we indeed find a low-energy collective electronic motion coupled with quantum phonons even if the energy of photoexcitation is away from this energy. For a Mott insulator on a lattice simplified from the structure of $κ-\text{(BEDT-TTF)}_2X$, however, such a collective motion does not appear, and quantum phonons are hardly excited.
Źródło:
Acta Physica Polonica A; 2012, 121, 2; 372-374
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Polar Phonons in Relaxor Ferroelectric 0.2PSN-0.4PMN-0.4PZN
Autorzy:
Macutkevič, J.
Kamba, S.
Pashkin, A.
Banys, J.
Bormanis, K.
Sternberg, A.
Powiązania:
https://bibliotekanauki.pl/articles/1813209.pdf
Data publikacji:
2008-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.30.-j
63.20.-e
71.55.Jv
Opis:
Relaxor ferroelectrics $0.2PbSc_{1//2}Nb_{1//2}O_3-0.4PbMg_{1//3}Nb_{2//3}O_3-0.4PbZn_{1//3}Nb_{2//3}O_3$ ceramics were studied by means of the Fourier transform infrared reflection and THz transmission spectroscopy in the temperature range of 20-500 K. On heating from low temperatures, the $A_1$ component of the strongly split $TO_1$ mode softens towards the Burns temperature, but the softening ceases near 400 K, which could be a signature of polar cluster percolation temperature.
Źródło:
Acta Physica Polonica A; 2008, 113, 3; 879-882
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 24

Ta witryna wykorzystuje pliki cookies do przechowywania informacji na Twoim komputerze. Pliki cookies stosujemy w celu świadczenia usług na najwyższym poziomie, w tym w sposób dostosowany do indywidualnych potrzeb. Korzystanie z witryny bez zmiany ustawień dotyczących cookies oznacza, że będą one zamieszczane w Twoim komputerze. W każdym momencie możesz dokonać zmiany ustawień dotyczących cookies