Effect of Two‐Dimensional Crystal Orbitals on Fermi Surfaces and Electron Transport in Three‐Dimensional Perovskite Oxides

2019 ◽  
Vol 58 (17) ◽  
pp. 5503-5512 ◽  
Author(s):  
Maxwell Thomas Dylla ◽  
Stephen Dongmin Kang ◽  
G. Jeffrey Snyder
Keyword(s):  
Electron Transport ◽  
Three Dimensional ◽  
Perovskite Oxides ◽  
Two Dimensional ◽  
Fermi Surfaces ◽  
Crystal Orbitals ◽  
Dimensional Crystal

scholarly journals Two-Dimensional Fermi Surfaces in LaRuPO and LaFePO versus Three-Dimensional Fermi Surfaces in LaFe2P2

2009 ◽  
Vol 78 (5) ◽  
pp. 053705 ◽  
Author(s):  
Hiroshi Muranaka ◽  
Yusuke Doi ◽  
Keisuke Katayama ◽  
Hitoshi Sugawara ◽  
Rikio Settai ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Two Dimensional ◽  
Fermi Surfaces

Band Structure Theory for Extended Systems

2020 ◽  
pp. 246-278
Author(s):  
Jochen Autschbach
Keyword(s):  
Electronic Structure ◽  
Band Structure ◽  
Electron Gas ◽  
Three Dimensional ◽  
Structure Theory ◽  
Crystal Lattices ◽  
Hückel Theory ◽  
Periodic Linear ◽  
Crystal Orbitals ◽  
Dimensional Crystal

The electronic structure of infinite periodic systems (crystals) is treated with band structure theory, replacing molecular orbitals by crystal orbitals. The chapter starts out by introducing the electron gas and definitions of the Fermi momentum, the Fermi energy, and the density of states (DOS). A periodic linear combination of atomic orbitals (LCAO) type treatment of an infinite periodic system is facilitated by the construction of Bloch functions. The notions of energy band and band gap are discussed with band structure concepts, using the approximations made in Huckel theory (chapter 12). One, two, and three-dimensional crystal lattices and the associated reciprocal lattices are introduced. The band structures of sodium metal, boron nitride, silicon, and graphite, are discussed as examples of metals, insulators, semi-conductors, and semi-metals, respectively. The chapter concludes with a brief discussion of the projected DOS and measures to determine bonding or antibonding interactions between atoms in a crystal.

Structures of the ZrZn22 family: suprapolyhedral nanoclusters, methods of self-assembly and superstructural ordering

2009 ◽  
Vol 65 (3) ◽  
pp. 300-307 ◽  
Author(s):  
G. D. Ilyushin ◽  
V. A. Blatov
Keyword(s):  
Crystal Structures ◽  
Self Assembly ◽  
Topological Analysis ◽  
Three Dimensional ◽  
Topological Type ◽  
Point Symmetry ◽  
Two Dimensional ◽  
The Matrix ◽  
Nanocluster Precursor ◽  
Dimensional Crystal

A combinatorial topological analysis is carried out by means of the program package TOPOS4.0 [Blatov (2006), IUCr Comput. Commun. Newsl. 7, 4–38] and the matrix self-assembly is modeled for crystal structures of the ZrZn22 family (space group Fd\bar 3m, Pearson code cF184), including the compounds with superstructural ordering. A number of strict rules are proposed to model the crystal structures of intermetallics as a network of cluster precursors. According to these rules the self-assembly of the ZrZn22-like structures was considered within the hierarchical scheme: primary polyhedral cluster → zero-dimensional nanocluster precursor → one-dimensional primary chain → two-dimensional microlayer → three-dimensional microframework (three-dimensional supraprecursor). The suprapolyhedral cluster precursor AB 2 X 37 of diameter ∼ 12 Å and volume ∼ 350 Å3 consists of three polyhedra (one AX 16 of the \bar 43m point symmetry and two regular icosahedra BX 12 of the \bar 3m point symmetry); the packing of the clusters determines the translations in the resulting crystal structure. A novel topological type of the two-dimensional crystal-forming 4,4-coordinated binodal net AB 2, with the Schläfli symbols 3636 and 3366 for nodes A and B, is discovered. It is shown that the ZrZn22 superstructures are formed by substituting some atoms in the cluster precursors. Computer analysis of the CRYSTMET and ICSD databases shows that the cluster AB 2 X 37 occurs in 111 intermetallics belonging to 28 structure types.

scholarly journals EXPOENTE DE AVRAMI PELA EQUAÇÃO DE JMAK PARA MÉTODO NÃO-ISOTÉRMICO DE ANÁLISE TÉRMICA

2018 ◽  
Vol 1 (2) ◽  
Author(s):  
Salmo Moreira Sidel ◽  
Elio Idalgo ◽  
Keizo Yukimitu ◽  
João Carlos Silos Moraes ◽  
Fabio Alencar Dos Santos
Keyword(s):  
Crystal Growth ◽  
General Theory ◽  
Isothermal Crystallization ◽  
Crystallization Process ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Nucleation Process ◽  
Vitreous System ◽  
Isothermal Measurements ◽  
Dimensional Crystal

This work reports a discussion about of the general theory for phase transformations of Melh-Johnson-Avrami-Kolmogorov in process involving non-isothermal crystallization. This model allows determine as occurs the mechanism of the nucleus formation and of growth of crystalline phases during the crystallization process. To demonstrate the validity this theory, the Avrami exponent (n) of the LiO2-TeO2-WO3 vitreous system was determined from DSC non-isothermal measurements. The obtained results indicate that the nucleation process is volumetric with two-dimensional or three-dimensional crystal growth. DOI: http://dx.doi.org/10.30609/JETI.2018-2.5566

The generation of possible crystal structures of primary amides

1983 ◽  
Vol 388 (1794) ◽  
pp. 133-175 ◽  
Keyword(s):  
Crystal Structures ◽  
Van Der Waals ◽  
Three Dimensional ◽  
Close Packing ◽  
Two Dimensional ◽  
Coulomb Interactions ◽  
Primary Amide ◽  
Size And Shape ◽  
Dimensional Crystal ◽  
Hydrogen Bonded

Procedures are outlined for generation of crystal structures of primary amide molecules by constructing the possible ways in which the molecules may pack. For each given one- or two-dimensional hydrogen-bonded array, ensembles of three-dimensional crystal structures are generated by considering the possible ways in which the arrays may be juxtaposed. Observed and generated hypothetical molecular arrangements are analysed to highlight both favourable and unfavourable features, par­ticularly in terms of close packing principles, the size and shape of the molecule, van der Waals and Coulomb interactions and N-H ∙ ∙ ∙ O bonding geometry.

Cocrystals of 2,6-dichloroaniline and 2,6-dichlorophenol plus three new pseudopolymorphs of their coformers

2015 ◽  
Vol 71 (9) ◽  
pp. 804-813
Author(s):  
Valeska Gerhardt ◽  
Michael Bolte
Keyword(s):  
Crystal Packing ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Dimensional Network ◽  
Solvent Molecules ◽  
Dimensional Crystal

The structures of cocrystals of 2,6-dichlorophenol with 2,4-diamino-6-methyl-1,3,5-triazine, C6H4Cl2O·C4H7N5, (III), and 2,6-dichloroaniline with 2,6-diaminopyrimidin-4(3H)-one andN,N-dimethylacetamide, C6H5Cl2N·C4H6N4O·C4H9NO, (V), plus three new pseudopolymorphs of their coformers, namely 2,4-diamino-6-methyl-1,3,5-triazine–N,N-dimethylacetamide (1/1), C4H7N5·C4H9NO, (I), 2,4-diamino-6-methyl-1,3,5-triazine–N-methylpyrrolidin-2-one (1/1), C4H7N5·C5H9NO, (II), and 6-aminoisocytosine–N-methylpyrrolidin-2-one (1/1), C4H6N4O·C5H9NO, (IV), are reported. Both 2,6-dichlorophenol and 2,6-dichloroaniline are capable of forming definite synthon motifs, which usually lead to either two- or three-dimensional crystal-packing arrangements. Thus, the two isomorphous pseudopolymorphs of 2,4-diamino-6-methyl-1,3,5-triazine,i.e.(I) and (II), form a three-dimensional network, while theN-methylpyrrolidin-2-one solvate of 6-aminoisocytosine,i.e.(IV), displays two-dimensional layers. On the basis of these results, attempts to cocrystallize 2,6-dichlorophenol with 2,4-diamino-6-methyl-1,3,5-triazine, (III), and 2,6-dichloroaniline with 6-aminoisocytosine, (V), yielded two-dimensional networks, whereby in cocrystal (III) the overall structure is a consequence of the interaction between the two compounds. By comparison, cocrystal–solvate (V) is mainly built by 6-aminoisocytosine forming layers, with 2,6-dichloroaniline and the solvent molecules arranged between the layers.

Layer structure estimation of three-dimensional crystal and two-dimensional molecular film for fluorinated comb copolymers

2008 ◽  
Vol 46 (5) ◽  
pp. 534-546 ◽  
Author(s):  
Atsuhiro Fujimori ◽  
Hiroko Hoshizawa ◽  
Satoshi Kobayashi ◽  
Kaname Kanai ◽  
Yukio Ouchi ◽  
...  
Keyword(s):  
Layer Structure ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Structure Estimation ◽  
Molecular Film ◽  
Dimensional Crystal
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