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Wyszukujesz frazę "Mn" wg kryterium: Temat


Tytuł:
Electronic Structure and Fermiology of High-T$\text{}_{c}$ Superconductors
Autorzy:
Bansil, A.
Kaprzyk, S.
Powiązania:
https://bibliotekanauki.pl/articles/1929378.pdf
Data publikacji:
1993-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.25.-s
74.20.Mn
74.25.Jb
Opis:
We briefly discuss some of our recent results in three areas, all related to issues concerning the electronic structure and fermiology of the high-T$\text{}_{c}$'s. (i) First-principles band theory based computations of the electron-positron momentum density relevant for the interpretation of the positron annihilation (2D-ACAR) experiments; results for YBa$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{7}$ are discussed. (ii) Another k-resolved spectroscopy where such first-principles comparisons between the computed and measured spectral intensities have been crucially important is the angle-resolved photoemission experiment; we discuss results for the (001)-surface of YBa$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{7}$ where computations yield considerable insight into the nature and origin of the spectral signal associated with the CuO$\text{}_{2}$ plane bands. (iii) The study of effects of substitutions and of oxygen-vacancy disorder in the high-T$\text{}_{c}$'s; here results for the LaSrCuO$\text{}_{4}$, and Ba-K-Bi-O and Ba-Pb-Bi-O systems, with focus on the nature of the van Hove singularity in the vicinity of the Fermi energy are presented.
Źródło:
Acta Physica Polonica A; 1993, 84, 1; 7-20
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Inelastic Electron Scattering in Double-Barrier Resonant Tunneling Structure Revealed with Photoexcitation
Autorzy:
Figielski, T.
Mąkosa, A.
Wosiński, T.
Harness, P. C.
Singer, K. E.
Powiązania:
https://bibliotekanauki.pl/articles/1929767.pdf
Data publikacji:
1993-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.40.Gk
85.30.Mn
Opis:
We investigated current-voltage and photocurrent-voltage characteristics of a double-barrier resonant tunneling structure based on AlGaAs. To explain the observed "double-step" feature of the characteristics, we have proposed a mechanism including a multiple phonon emission of an electron dwelling in the quantum well.
Źródło:
Acta Physica Polonica A; 1993, 84, 4; 817-819
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Traversal Time through Double-Barrier Resonant Tunneling Structure
Autorzy:
Figielski, T.
Powiązania:
https://bibliotekanauki.pl/articles/1929681.pdf
Data publikacji:
1993-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.40.Gk
85.30.Mn
Opis:
There are certain confusing statements in the literature concerning a physical time that is responsible for a high-frequency limit in operation of double-barrier resonant tunneling devices. Here, it is shown that an electron traversal time, introduced earlier by ours, exhibits no singularity on resonance and might be a good candidate for the quantity in question.
Źródło:
Acta Physica Polonica A; 1993, 84, 3; 587-589
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of Statistical Spin Liquid Concept to High-Temperature Superconductivity
Autorzy:
Byczuk, K.
Spałek, J.
Powiązania:
https://bibliotekanauki.pl/articles/1930571.pdf
Data publikacji:
1994-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.27.+a
74.20.Mn
Opis:
We apply the concept of statistical spin liquid, in which the doubly occupied quasimomentum configurations {|k⇅⟩} for quasiparticles are excluded from the Fock space, to a planar superconductor with real space pairing. The results compare very well with experimental data for the cuprates, namely (i) the condensed state appears only for the number of holes 0 < δ < 0.15-0.25; (ii) the temperature dependence of the gap is close to the BCS result, but the gap has systematically lower value and is of an extended s-wave form.
Źródło:
Acta Physica Polonica A; 1994, 85, 2; 337-340
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electron Spectrum and Dieleclric Susceptibility of the Hubbard Model with Local Lattice Anharmonicity
Autorzy:
Stasyuk, I. V.
Shvaika, A. M.
Powiązania:
https://bibliotekanauki.pl/articles/1930577.pdf
Data publikacji:
1994-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.20.Mn
71.45.Gm
Opis:
The investigation of single-electron spectrum of the Hubbard model with local lattice anharmonicity is performed. The influence of the interaction with the vibrational subsystem on the effective exchange constant is considered. The static transverse dielectric susceptibility of the model is calculated. Analysis of the possible dielectric anomalies is performed on this basis.
Źródło:
Acta Physica Polonica A; 1994, 85, 2; 363-366
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Indirect RKKY-Type Interaction by Direct Oxygen Hopping
Autorzy:
Rodriguez-Nuńez, J.
Coqblin, B.
Beck, H.
Konior, J.
Powiązania:
https://bibliotekanauki.pl/articles/1930566.pdf
Data publikacji:
1994-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.20.Mn
74.25.Jb
Opis:
The three-band Emery model, describing the holes in the CuO$\text{}_{2}$ planes of the high-temperature superconducting oxides, is considered. The model includes the direct oxygen-oxygen hopping integral t$\text{}_{pp}$. The exact Bogolyubov transformation is used to exclude one oxygen band and obtain a two-dimensional Anderson model. Afterward, the effective Hamiltonian is obtained by eliminating the second oxygen band with the use of two approximate canonical transformations. The effective Hamiltonian describes the spins residing on the copper sites and interacting through an indirect interaction J$\text{}_{SX}$(R), where R is the distance between two copper ions. J$\text{}_{SX}$(R) depends on the doping rate δ and is a decaying function of R. Numerical results for J$\text{}_{SX}$(R) are given for different doping rates δ for the case of parabolic bands. The obtained interaction J$\text{}_{SX}$(R), when added to the original antiferromagnetic interaction (present in oxides at δ = 0), might lead to a frustration of the long-range antiferromagnetic ordering upon doping.
Źródło:
Acta Physica Polonica A; 1994, 85, 2; 317-322
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Magnetic Field on Fine Structure of Tunnel Current in Double-Barrier Resonant-Tunneling Devices
Autorzy:
Belyaev, A. E.
Vitusevich, S. A.
Glavin, B. A.
Mąkosa, A.
Dobrowolski, W.
Powiązania:
https://bibliotekanauki.pl/articles/1933716.pdf
Data publikacji:
1995-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.40.Gk
85.30.Mn
Opis:
An effect of magnetic field on a fine oscillatory structure revealed in the resonant current flowing through double-barrier resonant-tunneling devices is examined. It is found that the observed variation of the fine structure in a magnetic field parallel to the current direction differs considerably from that appearing in tunnel current flowing through single-barrier structures. Experimental results are explained in terms of the quantum interference effect arising in structures having wide spacer layers.
Źródło:
Acta Physica Polonica A; 1995, 88, 4; 675-678
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fine Structure of Resonant-Tunneling Peak in GaAs/AlAs Double-Barrier Heterostructure
Autorzy:
Vitusevich, S. A.
Figielski, T.
Mąkosa, A.
Wosiński, T.
Belyaev, A. E.
Konakova, R. V.
Kravchenko, L. N.
Powiązania:
https://bibliotekanauki.pl/articles/1872937.pdf
Data publikacji:
1995-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.40.Gk
85.30.Mn
Opis:
For the first time we observed a fine oscillatory structure, with the period of 36 mV, of the resonant tunneling peak in the current-voltage characteristic of a double-barrier heterostructure. We attribute it to a sequential single-phonon emission of ballistic electrons which tunneled out from the quantum well through the collector barrier.
Źródło:
Acta Physica Polonica A; 1995, 87, 2; 377-380
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Three- versus Two-Dimensional Electron Gas Injection in Resonant Tunnelling
Autorzy:
Figielski, T.
Wosiński, T.
Mąkοsa, A.
Kaniewska, M.
Regiński, K.
Powiązania:
https://bibliotekanauki.pl/articles/1933735.pdf
Data publikacji:
1995-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.40.Gk
85.30.Mn
Opis:
A small "precursor" of resonance is observed before the main resonance peak in the current-voltage characteristic of double-barrier resonant-tunnelling devices. The competition between the precursor and main-peak current is examined within the temperature range 4.2-400 K. The precursor is interpreted as 3DEG contribution to the resonant tunnelling dominated by a 2DEG injection from a triangular well formed under bias in the emitter spacer layer.
Źródło:
Acta Physica Polonica A; 1995, 88, 4; 707-710
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Interface Roughness on Resonant Tunnelling in Double-Barrier Heterostructures
Autorzy:
Figielski, T.
Wosiński, T.
Mąkosa, A.
Powiązania:
https://bibliotekanauki.pl/articles/1950747.pdf
Data publikacji:
1996-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.40.Gk
85.30.Mn
68.35.Ct
Opis:
We argue that the well-boundary roughness in a double-barrier heterostructure induces subsidiary subbands in the quantum well which, in turn, lead to the appearance of a broad shoulder beyond the principal resonance peak in the current-voltage characteristics.
Źródło:
Acta Physica Polonica A; 1996, 90, 4; 777-780
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetically Controlled Interference of Ballistic Electrons Tunnelled throughout the Double-Barrier Resonator
Autorzy:
Figielski, T.
Wosiński, T.
Mąkosa, A.
Dobrowolski, W.
Vitusevich, S. A.
Belyaev, A. E.
Powiązania:
https://bibliotekanauki.pl/articles/1950748.pdf
Data publikacji:
1996-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.40.Gk
85.30.Mn
Opis:
An effect of magnetic field normal to the tunnel current on the amplitude and phase of the fine oscillatory structure, discovered in the resonance current-voltage curve in double-barrier AlAs/GaAs heterostructures, has been examined. All the obtained results are consistently explained in terms of the interference of ballistic electrons, escaped from the quantum well, in the collector part of the structure.
Źródło:
Acta Physica Polonica A; 1996, 90, 4; 781-784
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Tunnel Current Features Caused by Defect Assisted Process in Resonant-Tunnelling Structures
Autorzy:
Belyaev, A. E.
Vitusevich, S. A.
Glavin, B. A.
Konakova, R. V.
Dobrowolski, W.
Mąkosa, A.
Kravchenko, L. N.
Gornev, E. S.
Powiązania:
https://bibliotekanauki.pl/articles/1947897.pdf
Data publikacji:
1996-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.40.Gk
85.30.Mn
Opis:
An extra channel of electron tunnelling through a double-barrier resonant-tunnelling GaAs/AlGaAs heterostructure caused by impurity assisted tunnelling was identified. We argue that it is due to DX centres associated with dopant donor atoms which diffused into the AlGaAs barrier layer.
Źródło:
Acta Physica Polonica A; 1996, 90, 4; 727-730
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Tunneling in Semiconductor Nanostructures: Physics and Devices
Autorzy:
Lüth, H.
Powiązania:
https://bibliotekanauki.pl/articles/1946763.pdf
Data publikacji:
1996-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.80.Ey
73.40.Gk
85.30.Mn
Opis:
Since modern semiconductor epitaxy techniques have reached the present level of perfectness, resonant tunneling through double barrier structures has attracted new interest, also with respect to novel device applications. The present review shortly discusses the underlying physical concepts of resonant tunneling through semiconductor multiple heterostructures. Beside resonant tunneling diodes also concepts for tunneling transistors are discussed. In particular, a novel 2D-2D tunnel transistor is presented, in which tunneling between two neighboring two-dimensional electron gases yields current-voltage characteristics with two types of instabilities depending on the applied gate voltage. Scaling down the lateral dimensions of a resonant tunneling diode leads to quantum boxes or dots, in which the effect of single electron tunneling with Coulomb-blockade can be observed. The underlying physics is discussed on the basis of recent experiments and theoretical calculations. Finally some possible future applications both of resonant tunneling diodes and of single electron devices are presented.
Źródło:
Acta Physica Polonica A; 1996, 90, 4; 667-679
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Coherent and Sequential Tunneling in High Magnetic Field
Autorzy:
Belyaev, A. E.
Vitusevich, S. A.
Maude, D.
Portal, J. C.
Powiązania:
https://bibliotekanauki.pl/articles/1968012.pdf
Data publikacji:
1997-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.40.Gk
85.30.Mn
Opis:
In the resonant tunneling diode incorporating a wide one-sided spacer layer, an oscillation picture has been studied in both polarities of the applied voltage in high magnetic field. The results lead to the conclusion that the interference between the electron waves running in the forward direction and the ones reflected at some potential step can occur in both the emitter and collector regions. The characteristic lengths corresponding to the path of the ballistic motion of electrons were estimated. An exchange enhancement of the electronic g-factor in two-dimensional systems was observed.
Źródło:
Acta Physica Polonica A; 1997, 92, 4; 704-708
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Non-Fermi Liquid States of a General Model of Copper-Oxide Metals
Autorzy:
Varma, C. M.
Powiązania:
https://bibliotekanauki.pl/articles/1953178.pdf
Data publikacji:
1997-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.10.Hf
74.72.-h
74.20.Mn
74.25.-q
Opis:
A summary is given of the minimum requirements posed by experimental results on a theory of copper-oxide metals and of the recent solution of a model of copper-oxygen bonding and anti-bonding bands with the most general two-body interactions allowable by symmetry which satisfies these requirements. Several experiments were proposed to test the theory.
Źródło:
Acta Physica Polonica A; 1997, 91, 1; 191-201
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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