Temat: 71.15.-m - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Binding Energy of an Off-Center Hydrogenic Donor Impurity in a Finite Confining Potential Quantum Well
Autorzy:: Mikhail, I. F. I.
Ismail, I. M. M.
Tematy:: 71.15.-m
71.55.-i; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/2047296.pdf Link otwiera się w nowym oknie
Opis:: The binding energy of an off-center hydrogenic donor impurity in a finite confining potential quantum well was calculated by using a variational method of the Bastard type. New analytical expressions for the binding energy and for the initial deviation from the result of an infinite confining potential well were derived for the ground energy state. The sign of the initial deviation was found to depend on the location of the impurity. The analytical expressions were utilized further to derive some other important parameters.
Dostawca treści:: Biblioteka Nauki

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na półce

Skocz do pozycji: 2.

Tytuł:: The Overlapping Muffin-Tin Approximation
Autorzy:: Zwierzycki, M.
Andersen, O.
Tematy:: 71.15.-m
71.15.Ap; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1810287.pdf Link otwiera się w nowym oknie
Opis:: We present the formalism and demonstrate the use of the overlapping muffin-tin approximation. This fits a full potential to a superposition of spherically symmetric short-ranged potential wells plus a constant. For one-electron potentials of this form, the standard multiple-scattering methods can solve Schrödingers' equation correctly to 1st order in the potential overlap. Choosing an augmented-plane-wave method as the source of the full potential, we illustrate the procedure for diamond-structured Si. First, we compare the potential in the Si-centered overlapping muffin-tin approximation with the full potential, and then compare the corresponding overlapping muffin-tin approximation N-th order muffin-tin orbital and full-potential linear augmented plane wave band structures. We find that the two latter agree qualitatively for a wide range of overlaps and that the valence bands have a root mean squared deviation of 20 meV/electron for 30% radial overlap. Smaller overlaps give worse potentials and larger overlaps give larger 2nd-order errors of the multiple-scattering method. To further remove the mean error of the bands for small overlaps is simple.
Dostawca treści:: Biblioteka Nauki

Artykuł

na półce

Skocz do pozycji: 3.

Tytuł:: Magnetic Susceptibility of Mesoscopic Systems
Autorzy:: Wałcerz, S.
Tematy:: 71.24.+q
71.70.Di
71.15.-m; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1955458.pdf Link otwiera się w nowym oknie
Opis:: The Onsager description of de Haas-van Alphen oscillations and the magnetic translation group approach are combined in order to argue that the magnetic susceptibility of mesoscopic systems is assumed to reveal some features different than those of a bulk sample. Firstly, due to a discrete nature of magnetic field that has to be taken into account while dealing with the mesoscopic scale phenomena, the susceptibility should vary in a discrete way, too. Secondly, the susceptibility should depend on both the size and the shape of the system.
Dostawca treści:: Biblioteka Nauki

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na półce

Skocz do pozycji: 4.

Tytuł:: Multi-Scale Simulations of Semiconductor Nanostructures
Autorzy:: Zieliński, M.
Tematy:: 73.21.La
78.67.Hc
71.15.-m
71.15.Qe; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1419515.pdf Link otwiera się w nowym oknie
Opis:: We demonstrate a multi-domain scheme for calculation of electronic and optical properties of semiconductor nanostructures. Three progressively smaller computational domains are used for strain simulation, single particle states calculation and computation of the Coulomb scattering matrix elements. Proposed approach offers a significant reduction of computational time and memory savings without sacrificing the accuracy of obtained spectra. We illustrate this method on the example of InAs/InP self-assembled quantum dots.
Dostawca treści:: Biblioteka Nauki

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na półce

Skocz do pozycji: 5.

Tytuł:: Electronic and Magnetic Properties of $Co_{3}V_{2}O_{8}$ Compound
Autorzy:: Jezierski, A.
Szymczak, R.
Szymczak, H.
Kaczkowski, J.
Tematy:: 71.20.-b
71.15.-m
71.15.Ap
71.15.Mb
71.20.Be; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1810487.pdf Link otwiera się w nowym oknie
Opis:: The band structures and the magnetic properties of $Co_{3}V_{2}O_{8}$ compound have been calculated by ab initio scalar-relativistic full potential local orbital method within the local spin density approximation. The band calculations were performed for para-, ferro-, and antiferromagnetic $Co_{3}V_{2}O_{8}$ compounds. The main contribution to the density of states at the Fermi energy comes from minority 3d states of cobalt atoms.
Dostawca treści:: Biblioteka Nauki

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na półce

Skocz do pozycji: 6.

Tytuł:: On the Neglect of Local Coulomb Interaction on Oxygens in Perovskites Described by the Multiband d-p Model
Autorzy:: Rościszewski, K.
Oleś, A.
Tematy:: 71.15.-m
75.25.Dk
75.47.Lx; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1029759.pdf Link otwiera się w nowym oknie
Opis:: On the example of TiO₄ layer (such as realized in Sr₂TiO₄) we study electronic structure of multiband d-p models describing transition metal perovskites. As suggested by experiment, the studied system is predicted to be a robust nonmagnetic insulator. A realistic treatment of electronic structure requires one to introduce non-zero Coulomb local interactions at 2p oxygen orbitals. However, up till now majority of papers based upon multiband models made an approximation of neglecting such interactions. We show that this simplification does not lead to serious problems in predictions of the electronic structure provided the Coulomb interactions at titanium ions and charge transfer gap are suitably renormalized (so they become entirely different with respect to the true microscopic d-p model parameters).
Dostawca treści:: Biblioteka Nauki

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na półce

Skocz do pozycji: 7.

Tytuł:: Diagrammatic Perturbation Technique for a Quantum Dot Connected to Superconducting Leads
Autorzy:: Pokorný, V.
Janiš, V.
Novotný, T.
Žonda, M.
Tematy:: 71.15.-m
73.21.La
74.50.+r; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1201960.pdf Link otwiera się w nowym oknie
Opis:: We study spectral properties of a quantum dot attached to two superconductors with nonzero phase difference. The system is described as a single-impurity Anderson model coupled to BCS superconducting leads. We utilize diagrammatic perturbation expansion in the Coulomb interaction to capture relevant physical phenomena, particularly the effect of the Coulomb interaction on the Andreev bound states present in the electronic spectrum. Results of the Hartree-Fock and the random phase approximations at zero temperature are presented.
Dostawca treści:: Biblioteka Nauki

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na półce

Skocz do pozycji: 8.

Tytuł:: Coupled Multiphysics Models for the Analysis οf the Conduction and Valence Band Eigenenergies in Cylindrical Quantum Dots
Autorzy:: Prabhakar, S.
Takhtamirov, E.
Melnik, R.
Tematy:: 71.15.-m
73.21.La
62.23.Eg; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1490797.pdf Link otwiera się w nowym oknie
Opis:: We develop a mathematical model for the analysis of conduction and valence band eigenenergy in quantum dots. We apply the model to study the band structure calculations of low dimensional semiconductor nanostructures such as wurtzite AlN/GaN quantum dots in cylindrical coordinates in presence of applied magnetic field along z-direction. We use a finite element method to solve the resulting model and to obtain eigenvalues and wave functions of cylindrical quantum dots. We provide details of the methodology of solution and appropriate boundary conditions. A special attention is given to the case of applied magnetic field along z-direction, we found localized eigenstates and wave functions in the conduction and valence bands for which our results open new possibilities for the design of the optoelectronics devices where the combination of electron-hole pairs can be used as tuning parameters.
Dostawca treści:: Biblioteka Nauki

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na półce

Skocz do pozycji: 9.

Tytuł:: Computer Modeling of Point Defects, Impurity Self-Ordering Effects and Surfaces in Advanced Perovskite Ferroelectrics
Autorzy:: Borstel, G.
Kotomin, E. A.
Eglitis, R. I.
Heifets, E.
Tematy:: 61.72.-y
71.15.-m
68.35.-p; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/2014368.pdf Link otwiera się w nowym oknie
Opis:: The calculated optical properties of basic point defects - F-type centers and hole polarons - in KNbO$\text{}_{3}$ perovskite crystals are used for the interpretation of available experimental data. The results of quantum chemical calculations for perovskite KNb$\text{}_{x}$Ta$\text{}_{1-x}$O$\text{}_{3}$ solid solutions are presented for x=0, 0.125, 0.25, 0.75, and 1. An analysis of the optimized atomic and electronic structure clearly demonstrates that several nearest Nb atoms substituting for Ta in KTaO$\text{}_{3}$ - unlike Ta impurities in KNbO$\text{}_{3}$ - reveal a self-ordering effect, which probably triggers the ferroelectricity observed in KNb$\text{}_{x}$Ta$\text{}_{1-x}$O$\text{}_{3}$. Lastly, the (110) surface relaxations are calculated for SrTiO$\text{}_{3}$ and BaTiO$\text{}_{3}$ perovskites. The positions of atoms in 16 near-surface layers placed atop a slab of rigid ions are optimized using the classical shell model. Strong surface rumpling and surface-induced dipole moments perpendicular to the surface are predicted for both the O-terminated and Ti-terminated surfaces.
Dostawca treści:: Biblioteka Nauki

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na półce

Skocz do pozycji: 10.

Tytuł:: Influence of Local Environment on the Electronic Structure and Magnetic Properties of Ni$\text{}_{1-x}$Cu$\text{}_{x}$MnSb Alloys
Autorzy:: Jezierski, A.
Szytuła, A.
Tematy:: 31.15.Ar
31.15.Ew
71.15.Mb
71.15.-m
71.15.La
71.20.-b
71.20.Be; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/2013241.pdf Link otwiera się w nowym oknie
Opis:: The magnetic ordering in Ni$\text{}_{1-x}$Cu$\text{}_{x}$MnSb alloys changes from ferromagnetic (x=0) to antiferromagnetic (x=1). The X-ray and neutron diffraction showed that the systems crystallise in C1$\text{}_{b}$ type structure. We present an influence of the local chemical ordering on the electronic and magnetic properties of Ni$\text{}_{1-x}$Cu$\text{}_{x}$MnSb alloys. The band structure and the magnetic moments were calculated by the spin-polarised linear muffin-tin orbital in the atomic sphere approximation method for the experimental values of the lattice parameters. The magnetic moment of Mn increases from 3.8 μ$\text{}_{B}$ for x=0 to 4.18 μ$\text{}_{B}$ for x=1.
Dostawca treści:: Biblioteka Nauki

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