Temat: 61.50.Em - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Wreath Product in Factorization of Holosymmetric Group
Autorzy:: Florek, W.
Lulek, T.
Tematy:: 61.50.Em
02.20.+b; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1887747.pdf Link otwiera się w nowym oknie
Opis:: The holosymmetric group Q of an n-dimensional crystal lattice determined by a given lattice basis B is considered. This group is contained in the n-dimensional orthogonal group O(n) so its elements preserve the orthogonality of basis vectors and their lengths. These conditions yield the decomposition of lattice basis into orthogonal sublattices and next the factorization of the holosymmetric group, which can be written as a direct product of complete monomial groups of k-dimensional (k ≤ n) holosymmetric groups. Simple, decomposable and primitive holosymmetric groups are discussed. The results for n ≤ 4 are presented.
Dostawca treści:: Biblioteka Nauki

Artykuł

Skocz do pozycji: 2.

Tytuł:: Superionic Phase Transition in Rb$\text{}_{4}$LiH$\text{}_{3}$(SeO$\text{}_{4}$)$\text{}_{4}$ Single Crystals
Autorzy:: Połomska, M.
Hilczer, B.
Wolak, J.
Pietraszko, A.
Tematy:: 61.50.Em
62.20.Dc
77.22.Gm; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1931312.pdf Link otwiera się w nowym oknie
Opis:: Derivatographic, dielectric and complex impedance studies of Rb$\text{}_{4}$LiH$\text{}_{3}$(SeO$\text{}_{4}$)$\text{}_{4}$ crystals revealed a superionic phase transition at T$\text{}_{s}$ ≈ 448 K. The bulk conductivity rises from 10$\text{}^{-6}$ to 10$\text{}^{-4}$ (Ωm)$\text{}^{-1}$ at T$\text{}_{s}$, and the activation energy of conductivity in the direction of crystal axes a and b (where a = b for tetragonal symmetry) W$\text{}_{a}$ = W$\text{}_{b}$ decreases from 0.94 eV in the low temperature phase to the value of 0.27 eV at T > T$\text{}_{s}$. The analysis of the results of X-ray studies at room temperature and at 450 K indicates that the fast ion transport, characterized by low activation energy, is related to the delocalization of the H2 protons in the O(12)-H2-O(24) bonds linking the Se(1)O$\text{}_{4}$ and Se(2)O$\text{}_{4}$ tetrahedra. The "cogwheel" mechanism is suggested to be involved in the fast proton transport.
Dostawca treści:: Biblioteka Nauki

Artykuł

Skocz do pozycji: 3.

Tytuł:: Ground Shallow Donor State of III-V Compounds for Arbitrary Magnetic Field
Autorzy:: Obuchowicz, A.
Własak, J.
Tematy:: 78.20.Ls
61.50.Em
71.55.-i; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1921601.pdf Link otwiera się w nowym oknie
Opis:: Theory of shallow donor in III-V semiconductors in the presence of magnetic field is reinvestigated. Considerations are performed within the 3-level Kane model. In order to avoid singularities caused by the Coulomb potential we divide it into short- and long-range components. The latter one is the slowly varying potential and contrary to the Coulomb potential it satisfies all demands for envelope function equation. The short-range part is contributing to a chemical shift. Calculation of energies of two possible spin states of ground donor level are then performed using variational method.
Dostawca treści:: Biblioteka Nauki

Artykuł

Skocz do pozycji: 4.

Tytuł:: Magnetooptics of III-V Compounds in Many Band Model Approach
Autorzy:: Obuchowicz, A.
Wlasak, J.
Tematy:: 78.20.Ls
61.50.Em
71.55.-i; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1886749.pdf Link otwiera się w nowym oknie
Opis:: III-V semiconducting compounds in the presence of a magnetic field are considered. The 14 x 14 effective hamiltonian in the frame of 5-level model is obtained. Directional dependence of selection rules are obtained. Shallow donor levels in the frame of spherical 3-level model are also considered. New trial functions suitable for a whole range of magnetic field are proposed. It is found that the energy as well as the variational function of each magnetodonor level is a continuous function of the magnetic field.
Dostawca treści:: Biblioteka Nauki

Artykuł

Skocz do pozycji: 5.

Tytuł:: Mac Lane Method for Determination of Extensions of Finite Groups. I. A Review in the Context of Structure of Condensed Matter
Autorzy:: Lulek, T.
Tematy:: 02.20.+b
02.40.+m
03.20.+i
61.50.Em; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1920925.pdf Link otwiera się w nowym oknie
Opis:: The problem of classification of all extensions of a finite group Q by an Abelian group T has been reviewed using cohomology of groups and fibre bundle picture. The relevance of this problem in condensed matter physics has been pointed out in the context of crystallography and gauge fields. The Mac Lane method of an effective construction of the corresponding second cohomology group as the quotient group of all operator homomorphisms vs. crossed homomorphisms from some free groups to T has been described in detail.
Dostawca treści:: Biblioteka Nauki

Artykuł

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