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Wyświetlanie 1-26 z 26
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:
Size Effects on Nanowire Phonon Thermal Conductivity: a Numerical Investigation Using the Boltzmann Equation
Autorzy:
Abouelaoualim, D.
Powiązania:
https://bibliotekanauki.pl/articles/2047359.pdf
Data publikacji:
2007-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
63.22.+m
87.15.Aa
Opis:
Analytical solution of the Boltzmann transport equation for phonon transport in Bi$\text{}_{0.95}$Sb$\text{}_{0.05}$ nanowire is obtained. Thermal conductivity was calculated from the analytical solution of the Boltzmann transport equation. We calculate the lattice thermal conductivity of Bi$\text{}_{0.95}$Sb$\text{}_{0.05}$ nanowire as a function of temperature for different wire thicknesses. The results show that thermal conductivity of nanowire can be significantly smaller than the bulk thermal conductivity. We show that low thermal conductivity Bi$\text{}_{0.95}$Sb$\text{}_{0.05}$ nanowire for thermoelectric applications would have a small diameter.
Źródło:
Acta Physica Polonica A; 2007, 112, 1; 49-54
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Resonant Raman Spectra of CdTe/ZnTe Self Assembled Quantum Dots
Autorzy:
Romčević, N.
Romčević, M.
Kostić, R.
Stojanović, D.
Abolmasov, B.
Karczewski, G.
Galazka, R.
Powiązania:
https://bibliotekanauki.pl/articles/1807840.pdf
Data publikacji:
2009-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
63.22.-m
78.30.Fs
78.55.Et
Opis:
In this paper we present Raman scattering and photoluminescence spectra measured on CdTe/ZnTe self assembled quantum dots. The photoluminescence spectrum has shown two main emission peaks, both connected with existing of quantum dots. One presents direct deexcitation to ground state and the other is optical phonon (οmega = 207.3 $cm^{-1}$)-assisted deexcitation. The registered multiphonon emission process depends on temperature. At low temperature phonon spectra shows line at 450 $cm^{-1}$ (TA + 2LO in ZnTe) and 595 $cm^{-1}$ (2LO + TO(Γ) in ZnTe).
Źródło:
Acta Physica Polonica A; 2009, 116, 1; 88-90
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Anharmonicity Effects in Nanocrystals Studied by Raman Scattering Spectroscopy
Autorzy:
Dohčević-Mitrović, Z.
Popović, Z.
Šćepanović, M.
Powiązania:
https://bibliotekanauki.pl/articles/1807800.pdf
Data publikacji:
2009-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
63.22.-m
78.67.Bf
78.30.-j
61.72.uj
Opis:
Phonon-phonon interactions were investigated in various nanocrystalline powders like anatase $TiO_{2-δ}$, pure $CeO_{2-δ}$ and ceria doped with Nd(Gd) analyzing temperature dependent Raman spectra of these systems. Phonon confinement model based on size, inhomogeneous strain and anharmonic effects was used to properly describe the evident changes present in the Raman spectra of pure and doped ceria nanocrystalline samples. In small particles of pure and doped ceria nanocrystals, when size effects have minor impact on Raman modes, four phonon anharmonic processes prevail under the three-phonon ones. When nanopowdered particles are grown enough size effects provoke changes of the anharmonic interactions when three-phonon coupling prevails over the four-phonon anharmonic processes. In nanocrystalline anatase $TiO_2$ evident blueshift of the most prominent $E_g$ Raman mode probably originates from dominant four-phonon anharmonic interactions.
Źródło:
Acta Physica Polonica A; 2009, 116, 1; 36-41
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Use of Phonon Confinement Model in Simulation οf Raman Spectra of Nanostructured Materials
Autorzy:
Grujić-Brojčin, M.
Šćepanović, M.
Dohcević-Mitrović, Z.
Popović, Z.
Powiązania:
https://bibliotekanauki.pl/articles/1807810.pdf
Data publikacji:
2009-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.07.Wx
78.30.-j
63.22.-m
07.05.Tp
Opis:
The simulation of the Raman spectra of nanostructured materials, where the effects of frequency shift and asymmetric broadening of the Raman modes play an important role, can be very useful in systematic characterization of these materials. Use of phonon confinement model for calculating Raman spectra of different nanomaterials is considered both from the viewpoint of different confinement function and the confinement strength, as well as the dimensionality of the confinement model. The phonon dispersion relations and the choice of their approximation are also studied. The influence of particle size distribution on the shape of the calculated spectra is discussed and contributions of Gaussian and asymmetric Gaussian distribution are compared. The effects of average and inhomogeneous strain on the behavior of simulated Raman spectra are also discussed. The results of the phonon confinement model are compared to the experimental spectra of $CeO_2$ and anatase $TiO_2$ nanopowders.
Źródło:
Acta Physica Polonica A; 2009, 116, 1; 51-54
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
High Pressure Raman Spectroscopy in Carbon Nanotubes
Autorzy:
Kourouklis, G.
Arvanitidis, J.
Christofilos, D.
Ves, S.
Powiązania:
https://bibliotekanauki.pl/articles/1807795.pdf
Data publikacji:
2009-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.67.Ch
78.30.Na
63.22.-m
62.50.-p
Opis:
This work focuses on the high pressure Raman study of carbon nanostuctures comprising of single- or double-wall carbon nanotubes. The detailed examination of the Raman peaks, especially those attributed to the radial breathing modes of the carbon nanotubes, as a function of pressure provides a wealth of information concerning the pressure response of individual nanotubes as well as the internal-external tube (intratube) interactions. The radial breathing modes of both the internal and the external tubes in double-wall carbon nanotubes show reduced pressure slope values as compared to the corresponding in single-wall carbon nanotubes. The reduced slopes for the internal tubes reflect the pressure screening effect inside the external tubes, while those for the external tubes their structural reinforcement due to the encapsulation of smaller diameter tubes in their interior. Moreover, the magnitude of the pressure screening effect depends strongly on the intratube spacing and thus on the intratube interaction. All the experimental observations are well reproduced qualitatively by means of theoretical calculations based on a simple phenomenological model.
Źródło:
Acta Physica Polonica A; 2009, 116, 1; 13-18
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nanocrystalline Materials: Interfaces and Mesoscopic Correlations Studied by Neutron Scattering
Autorzy:
Stuhr, U.
Wagner, W.
Kohlbrecher, J.
van Swygenhoven, H.
Powiązania:
https://bibliotekanauki.pl/articles/2035459.pdf
Data publikacji:
2002-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.46.+w
63.22.+m
75.20.En
75.50.Tt
Opis:
Nanocrystalline materials can exhibit properties which are considerably different from their coarse-grained counterparts, making them unique for basic or applied research and also very promising for potential applications. The topics which are addressed in the present paper are magnetic properties and magnetic correlations on the nanometer scale, mechanical properties, in particular the influence of grain boundaries on the elastic and plastic behaviour, and vibration modes of grain boundary atoms in nanostructured materials.
Źródło:
Acta Physica Polonica A; 2002, 102, 1; 109-122
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Low-Frequency Raman Spectroscopy of Pure and La-Doped $TiO_2$ Nanopowders Synthesized by Sol-Gel Method
Autorzy:
Šćepanović, M.
Aškrabić, S.
Grujić-Brojčin, M.
Golubović, A.
Dohčević-Mitrović, Z.
Kremenović, A.
Popović, Z.
Powiązania:
https://bibliotekanauki.pl/articles/1807845.pdf
Data publikacji:
2009-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.20.Fw
81.07.Wx
78.30.-j
63.22.-m
Opis:
Pure and La-doped titania $(TiO_2)$ nanopowders are synthesized by sol-gel technology. The crystallite sizes determined by X-ray diffraction measurements range from 10 to 15 nm. Dependence of structural and morphological characteristics of nanopowders on synthesis conditions and $La^{3+}$ content is investigated by the Raman spectroscopy. Very intensive modes observed in the Raman spectra of all nanopowder samples are assigned to anatase phase of $TiO_2$. Additional Raman modes of extremely low intensity can be related to the presence of a small amount of brookite amorphous phase in nanopowders, which is in accordance with the results of X-ray diffraction analysis. The particle size distribution in TiO_2 nanopowders was estimated from the low frequency Raman spectra, using the fact that the phonon modes in nanosized $TiO_2$ observed in the low frequency region (ω <40 $cm^{-1}$) can be well described by the elastic continuum model, assuming that nanoparticles are of perfect spherical shape and isotropic. The nanosized particle distribution obtained by this method is used for the calculation of the frequency and shape of the most intensive $E_g$ Raman mode in anatase $TiO_2$ by the phonon confinement model. The calculated broadening of this mode, associated with the particle size distribution, coincides well with the characteristics of $E_g$ mode observed in measured Raman spectra of $TiO_2$ nanopowders. This confirms the Raman spectroscopy method as a powerful tool for determination of particle size distribution in nanosized materials.
Źródło:
Acta Physica Polonica A; 2009, 116, 1; 99-102
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Effect of Substrate on Vibrational Properties of Single-Layer MoS₂
Autorzy:
Gołasa, K.
Molas, M.
Nogajewski, K.
Grzeszczyk, M.
Zinkiewicz, M.
Potemski, M.
Babiński, A.
Powiązania:
https://bibliotekanauki.pl/articles/1398570.pdf
Data publikacji:
2016-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
63.22.-m
71.35.-y
78.20.-e
78.30.-j
Opis:
We report on the Raman scattering from single-layer molybdenum disulfide (MoS₂) deposited on various substrates: Si/SiO₂, hexagonal boron nitride (h-BN), sapphire, as well as suspended. Room temperature Raman scattering spectra are investigated under both resonant (632.8 nm) and non-resonant (514.5 nm) excitations. A rather weak influence of the substrate on the Raman scattering signal is observed. The most pronounced, although still small, is the effect of h-BN, which manifests itself in the change of energy positions of the E' and A'₁ Raman modes of single-layer MoS₂. We interpret this modification as originating from van der Waals interaction between the MoS₂ and h-BN layers.
Źródło:
Acta Physica Polonica A; 2016, 130, 5; 1172-1175
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optical Properties of Molybdenum Disulfide $(MoS_2)$
Autorzy:
Gołasa, K.
Grzeszczyk, M.
Korona, K.
Bożek, R.
Binder, J.
Szczytko, J.
Wysmołek, A.
Babiński, A.
Powiązania:
https://bibliotekanauki.pl/articles/1399110.pdf
Data publikacji:
2013-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
63.22.-m
71.35.-y
78.20.-e
78.30.-j
Opis:
Research of a monolayer and a bulk $MoS_2$ is reported. The room temperature Raman spectra of the natural $MoS_2$ crystals for the both resonant (632.8 nm) and the non-resonant (532 nm) excitation are presented. The apparent differences observed in the spectra from the bulk and the one monolayer $MoS_2$ are discussed. In particular, the feature due to a first order scattering involving the LA(M) phonon in the resonance Raman spectrum of the one monolayer $MoS_2$ was observed and explained in terms of the disorder in the natural crystal. The disorder is also documented by the line-shape of the room-temperature photoluminescence spectra observed from both the bulk and the one monolayer $MoS_2$.
Źródło:
Acta Physica Polonica A; 2013, 124, 5; 849-851
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phonon Signatures of a Quantum Impurity with Induced Electron Pairing
Autorzy:
Barański, J.
Domański, T.
Powiązania:
https://bibliotekanauki.pl/articles/1374760.pdf
Data publikacji:
2014-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.63.Kv
73.23.Hk
74.45.+c
74.50.+r
63.22.-m
Opis:
We analyze the effective spectrum of a vibrating molecule coupled between one conducting and another superconducting electrode. The proximity effect induces electron pairing which is manifested by the subgap quasiparticle peaks (the Andreev states) whose broadening depends on a hybridization with the conducting electrode. On the other hand, the electron-phonon interaction leads to a multilevel structure with the polaronic states separated by the phonon energy. We inspect a combined effect of both these (polaronic and induced pairing) phenomena.
Źródło:
Acta Physica Polonica A; 2014, 126, 4a; A-73-A-76
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The In$\text{}_{4}$Se$\text{}_{3}$ Crystal as a Three-Dimensional Imitative Model of Phenomena in One-Dimensional Crystals
Autorzy:
Bercha, D. M.
Sznajder, M.
Bercha, A. I.
Kharkhalis, L. Yu.
Rushchanskii, K.
Powiązania:
https://bibliotekanauki.pl/articles/1969018.pdf
Data publikacji:
1998-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.20.Nr
71.45.-d
63.20.Dj
63.20.Kr
63.22.+m
Opis:
For three-dimensional charge carriers described by the dispersion law with quartic terms of the wave vector, the density of states function similar as in the one-dimensional case was determined. This similarity allows the Pekar and Dejgen condenson states in the continuum approximation to exist. The calculated phonon spectrum reveals optical vibrations of a very low frequency, which favours the electron-phonon interaction and creation of the condenson states.
Źródło:
Acta Physica Polonica A; 1998, 94, 2; 250-254
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Depth-Selective Study of Surface Crystallization in NANOPERM-Type Alloys
Autorzy:
Miglierini, M.
Hatala, T.
Bujdoš, M.
Powiązania:
https://bibliotekanauki.pl/articles/1382582.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
76.80.+y
75.70.i
71.55.Jv
65.80.-g
63.22.-m
63.50.-x
Opis:
Evolution of structure and magnetic order is studied in the $\text{}^{57}Fe_{81}Mo_{8}Cu_{1}B_{10}$ alloy by conversion electron and conversion X-ray $\text{}^{57}Fe$ Mössbauer spectrometry. Surface features exhibit differences at both sides of ribbon-shaped samples with respect to the screening depth. In the as-quenched state, traces of magnetite (in addition to bcc-Fe) are revealed only at the wheel side of the ribbon to the depth of about 200 nm. It is present also after annealing up to 510 °C, then it disappears. In deeper regions (down to 1 μm), magnetite is less abundant. At the air side, only bcc-Fe is detected, though the progress of crystallization is more pronounced here than at the wheel side. Vibration properties of the bulk of amorphous and nanocrystalline samples are obtained from experiments of nuclear inelastic scattering of synchrotron radiation using partial densities of phonon states.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 56-57
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Molecular Beam Epitaxy Growth for Quantum Cascade Lasers
Autorzy:
Kosiel, K.
Szerling, A.
Kubacka-Traczyk, J.
Karbownik, P.
Pruszyńska-Karbownik, E.
Bugajski, M.
Powiązania:
https://bibliotekanauki.pl/articles/1791281.pdf
Data publikacji:
2009-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.55.Px
81.15.Hi
85.60.-q
85.35.Be
73.63.-b
63.22.-m
72.80.Ey
73.61.Ey
78.66.Fd
Opis:
The fabrication of quantum cascade lasers emitting at 9 μm is reported. The devices operated in pulsed mode at up to 260 K. The peak powers recorded at 77 K were over 1 W and the slope efficiency η ≈ 0.5-0.6 W/A per uncoated facet. This has been achieved by the use of GaAs/$Al_{0.45}Ga_{0.55}As$ heterostructure, with the "anticrossed-diagonal" design. Double plasmon planar confinement with Al-free waveguide has been used to minimize absorption losses. The double trench lasers were fabricated using standard processing technology, i.e., wet etching and $Si_{3}N_{4}$ for electrical insulation. The quantum cascade laser structures have been grown by molecular beam epitaxy, with Riber Compact 21 T reactor. The stringent requirements - placed particularly on the epitaxial technology - and the influence of technological conditions on the device structure properties were presented and discussed in depth.
Źródło:
Acta Physica Polonica A; 2009, 116, 5; 806-813
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Lattice Thermal Conductivity of GaAs
Autorzy:
Ataullah Ansari, M.
Ashokan, V.
Indu, B.
Kumar, R.
Powiązania:
https://bibliotekanauki.pl/articles/1489863.pdf
Data publikacji:
2012-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
63.20.kd
66.70.Df
63.22.Rc
63.20.Ry
Opis:
A new approach to evaluate the relaxation times of various collision events responsible for thermal transport has been reported through which various deficiencies of earlier models of lattice thermal conductivity have been resolved. These investigations involve the evaluation of the phonon Green functions via a non-perturbative approach. The new expressions of relaxation times expressions for scattering of phonons by boundaries, atomic impurities, phonon-phonon scattering, electron-phonon scattering are the new features of the theory. The lattice thermal conductivity of three samples of GaAs has been analyzed on the basis of modified Callaway model and fairly good agreement between theory and experimental observations has been reported.
Źródło:
Acta Physica Polonica A; 2012, 121, 3; 639-646
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Novel Approach for Energy Spectrum Probing in Semiconducting Quantum Dots
Autorzy:
Zdrojek, M.
Wąsik, M.
Esplandiu, M.
Bachtold, A.
Powiązania:
https://bibliotekanauki.pl/articles/1419526.pdf
Data publikacji:
2012-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.22.Dj
73.23.Hk
73.63.Kv
Opis:
A new technique has been used to probe the electronic properties of quantum dots. Here we discuss the case of semiconducting CdSe dots. This technique allows us to fill (or empty) semiconducting quantum dot with many electrons. The detection scheme is based on an original approach where the investigated particle is attached to only one electrode, a carbon nanotube. The conductance of the nanotube is measured as a function of a gate voltage $(V_{g}),$ which allows the detection of individual electrons transferred onto the quantum dot. For certain range of $V_{g}$ we noticed no electron transfer which is attributed to the energy gap of the CdSe quantum dot. Our study shows that single-electron detection with carbon nanotube transistor represents a new strategy to study the separation between the electronic discrete energy levels of the semiconducting quantum dot.
Źródło:
Acta Physica Polonica A; 2012, 122, 2; 321-323
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Bond-Selective Excitation and Following Displacement of Ge Atoms in $GeTe//Sb_{2}Te_{3}$ Superlattice
Autorzy:
Makino, K.
Tominaga, J.
Kolobov, A.
Fons, P.
Hase, M.
Powiązania:
https://bibliotekanauki.pl/articles/1489973.pdf
Data publikacji:
2012-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.47.J-
63.22.Np
63.20.kd
63.20.kk
Opis:
Phase change random access memory devices made from chalcogenides compounds, such as $Ge_{2}Sb_{2}Te_{5}$, have attracted much attention because of their high-speed read-write and low power consumption capabilities. The phase change in $Ge_{2}Sb_{2}Te_{5}$ is thought to be characterized by the displacement of Ge atoms, accompanying relaxation of surrounding Sb and Te atoms. Here we examine a new approach, that is the manipulation of Ge-Te bonds using linearly-polarized femtosecond near-infrared optical pulses. As a result, p-polarized pump pulses are found to be more effective in inducing the precursor of phase change, probably due to the atomic arrangements along the unique axis of the superlattice structure.
Źródło:
Acta Physica Polonica A; 2012, 121, 2; 336-339
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electron Transmission through Graphene Bilayer Flakes
Autorzy:
Chico, L.
González, J.
Santos, H.
Pacheco, M.
Brey, L.
Powiązania:
https://bibliotekanauki.pl/articles/1419511.pdf
Data publikacji:
2012-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.22.-f
73.63.-b
Opis:
We investigate the electronic transport properties of a bilayer graphene flake contacted by two monolayer nanoribbons. This finite-size bilayer flake can be built by overlapping two semi-infinite ribbons. We study and analyze the electronic behavior of this structure by means of a tight-binding method and a continuum Dirac model. We have found that the conductance oscillates markedly between zero and the maximum value of the conductance, allowing for the design of electromechanical switches.
Źródło:
Acta Physica Polonica A; 2012, 122, 2; 299-303
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Lattice Dynamical Investigation of the Raman and the Infrared Wave Numbers of $MnWO_4$
Autorzy:
Gupta, H.
Ruby, -
Sinha, M.
Powiązania:
https://bibliotekanauki.pl/articles/1419784.pdf
Data publikacji:
2012-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.50.Ah
63.22.Dc
63.70.+h
75.10.Pq
78.30.-j
Opis:
A short-range force constant model has been applied using normal coordinate analysis to investigate the Raman and the infrared modes in multiferroic $MnWO_4$ having space group P2/c. The calculation of zone centre phonons has been made with eight stretching and seven bending force constants. The calculated Raman and infrared wave numbers are in good agreement with the observed ones. The potential energy distribution has also been investigated for determining the significance of contribution from each force constant toward the Raman and the infrared wave numbers.
Źródło:
Acta Physica Polonica A; 2012, 122, 1; 142-145
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Coupling between Electronic and Vibrational Excitations in Carbon Nanotubes Filled with $C_{60}$ Fullerenes
Autorzy:
Utko, P.
Ferone, R.
Krive, I.
Shekhter, R.
Jonson, M.
Monthioux, M.
Noé, L.
Nygård, J.
Powiązania:
https://bibliotekanauki.pl/articles/1492807.pdf
Data publikacji:
2011-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.63.Fg
73.63.Kv
73.23.Hk
73.22.Lp
71.38.-k
Opis:
We investigate the low-temperature electron transport through $C_{60}$ peapods, which are carbon nanotubes encapsulating $C_{60}$ fullerenes. We find that the temperature dependence of the Coulomb blockade oscillations in peapod quantum dots deviates from conventional Breit-Wigner behavior, showing signatures of the Franck-Condon blockade of conductance. This indicates the presence of a coupling between electronic states and vibrational excitations. Unlike for suspended empty nanotubes, these are not intrinsic vibrational modes of the tube but mechanical vibrations of the encapsulated fullerenes that affect the electronic transport. Fullerene peapods thus emerge as a new class of nanoelectromechanical systems.
Źródło:
Acta Physica Polonica A; 2011, 120, 5; 839-841
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Low Temperature Specific Heat of BiOX (X = Cl, Br, and I) Single Crystals
Autorzy:
Bunda, V.
Bunda, S.
Kajňakova, M.
Feher, A.
Syrkin, E.
Feodosyev, S.
Powiązania:
https://bibliotekanauki.pl/articles/1535050.pdf
Data publikacji:
2010-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
65.40.-b
63.22.Np
Opis:
Low temperature specific heat of layered bismuth oxyhalide crystals has been studied in the temperature range from 2 to 50 K in zero and 8 T magnetic field. The expected Debye-like behaviour at the lowest temperatures (below 4-5 K) is established. Linear dependences of entropy and the Debye temperature as cross-correlation parameters are established. The small values of the Debye temperature and peculiarities of phonon spectra at lowest temperatures are discussed.
Źródło:
Acta Physica Polonica A; 2010, 118, 5; 986-987
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electric Conductivity of Carbon Nanoparticles Stimulated by Electric Field
Autorzy:
Markowski, D.
Kempiński, W.
Kempiński, M.
Trybuła, Z.
Kaszyńska, K.
Śliwińska-Bartkowiak, M.
Powiązania:
https://bibliotekanauki.pl/articles/1535906.pdf
Data publikacji:
2010-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.22.Pr
73.21.La
73.23.Hk
73.25.+i
73.63.-b
73.23.-b
Opis:
Host-guest interactions can be the unique method of spin manipulation in nanoscale. Strong changes in spin localization are generated when potential barriers between nanographitic units of activated carbon fibers are modified by interaction with adsorbed molecules. Stronger modifications occur when dipolar guest molecules are stimulated with external electric field. We report experimental results which show the influence of electric field on the spin localization in activated carbon fibers.
Źródło:
Acta Physica Polonica A; 2010, 118, 3; 457-458
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Structural and Electronic Properties of Graphene Oxide and Reduced Graphene Oxide Papers Prepared by High Pressure and High Temperature Treatment
Autorzy:
Tokarczyk, M.
Kowalski, G.
Witowski, A.
Koziński, R.
Librant, K.
Aksienionek, M.
Lipińska, L
Ciepielewski, P.
Powiązania:
https://bibliotekanauki.pl/articles/1195411.pdf
Data publikacji:
2014-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.48.Gh
61.72.Dd
63.22.Rc
Opis:
"Graphene paper" prepared by new proprietary method involving high pressure and high temperature treatment in the reduction process show new possibilities in this area. Different phase content: multilayer and single layer graphene stacks recorded in this study for RGO samples are accompanied by the specific electric and optical parameters. We have found that process temperatures above 900°C play crucial role in structural and other properties. For the process temperature around 2000°C we found the onset of the graphitization in the samples.
Źródło:
Acta Physica Polonica A; 2014, 126, 5; 1190-1194
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
CVD Growth of Graphene Stacks on 4H-SiC (0001) Surface - X-ray Diffraction and Raman Spectroscopy Study
Autorzy:
Tokarczyk, M.
Kowalski, G.
Grodecki, K.
Urban, J.
Strupiński, W.
Powiązania:
https://bibliotekanauki.pl/articles/1399073.pdf
Data publikacji:
2013-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.48.Gh
61.72.Dd
63.22.Rc
Opis:
Features associated with short and prolonged growth time in the chemical vapor deposition process of growth of graphene stacks on SiC (0001) substrate are reported. In particular general bimodal (as far as $d_{002}$ interlayer spacing is concerned) distribution of graphene species across the surface of the samples is observed. It consists of thin few layer graphene coverage of most of the sample surface accompanied by thick graphite-like island distribution. It points to the two independent channels of graphene stacks growth with two characteristic growth rates.
Źródło:
Acta Physica Polonica A; 2013, 124, 5; 768-771
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Measuring the Energy Landscape in Single Semiconductor Nanowires
Autorzy:
Smith, L.
Jackson, H.
Yarrison-Rice, J.
Jagadish, Ch.
Powiązania:
https://bibliotekanauki.pl/articles/1419516.pdf
Data publikacji:
2012-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.22.-f
73.43.Fj
73.50.Gr
73.50.Pz
73.63.-b
78.30.Fs
78.35.+c
78.55.-m
78.67.-n
Opis:
With the ability to design and control the physical structure of nanostructures to tune their electronic properties, it is increasingly important to measure the electronic structure of single nanostructures. Here we describe a number of experimental techniques for measuring the electronic structure of single semiconductor nanowires. The advantages, disadvantages and limitations of these methods will be described.
Źródło:
Acta Physica Polonica A; 2012, 122, 2; 316-320
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Włączenie w rozwój. Rozwój jako proces współtworzenia i współuczestnictwa
Inclusion in Development. Development As a Process of Co-creation and Joint Participation
Autorzy:
Zdun, Magdalena M.
Powiązania:
https://bibliotekanauki.pl/articles/32062581.pdf
Data publikacji:
2023-12-30
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie
Tematy:
rozwój
włączenie
współtworzenie
współuczestnictwo
refleksyjność
ruch społeczny
development
inclusion
co-creation
joint participation
reflexivity
social movement
Opis:
Celem mniejszego artykułu jest przedstawienie nowego modelu partycypacji w rozwoju, odpowiadającego współczesnym uwarunkowaniom społecznym, gospodarczym i kulturowym. Do finalnej konstrukcji modelu wiodą klasyczne ustalenia teoretyczne i właściwe im kategorie pojęciowe. Ewolucjonizm dostarcza terminu roli społecznej i umieszcza włączenie w rozwój w polu napięć między jednostką a systemem. Modernizacja pozwala wiązać udział w rozwoju z typem woli, czyli intencją uczestnictwa. Wreszcie dialektyka umożliwia wychwycenie podstawowej dynamiki procesu, jak również uprawdopodobnia identyfikację zbiorowej kategorii uczestnictwa. Wydaje się, że współcześnie jest nią ruch społeczny. To on pełni rolę aksjologicznego zaplecza zmiany społecznej i daje się poznać jako wartościo-normatywna warstwa rozwoju, dzięki której rozwój może zostać scharakteryzowany jako proces współtworzenia i współuczestnictwa – proces, w którym partycypuje się biograficznie, refleksyjnie i międzypodmiotowo.
The purpose of the article is to present a new model of participation in development, corresponding to contemporary social, economic and cultural conditions. Classical theoretical findings and their respective conceptual categories lead to the final construction of the model. Evolutionism provides the term of social role and places participation in the field of tensions between the individual and the system. Modernization facilitates linking inclusion in development to the type of will, i.e. intention to participate. Finally, the dialectic makes it possible to capture the underlying dynamics of the process, and also to identify the collective category of participation, which seems to be represented by a contemporary social movement. It is that movement which acts as the axiological basis of social change and becomes the value-normative layer of development, through which that development can be characterized as a process of co-creation and joint participation, in which one participates biographically, reflectively and inter-subjectively.
Źródło:
Studia Humanistyczne AGH; 2023, 22, 2; 47-63
2084-3364
2300-7109
Pojawia się w:
Studia Humanistyczne AGH
Dostawca treści:
Biblioteka Nauki
Artykuł
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