scholarly journals Простые модели латеральных гетероструктур

2018 ◽  
Vol 60 (7) ◽  
pp. 1389
Author(s):  
С.Ю. Давыдов
Keyword(s):  
Charge Transfer ◽  
Density Of States ◽  
Function Method ◽  
Tight Binding ◽  
Tight Binding Approximation ◽  
Densities Of States ◽  
Infinite Lattices ◽  
Band Spectra ◽  
Analytical Expressions ◽  
Lateral Heterostructure

AbstractGeneral analytical expressions for densities of states of a lateral heterostructure, formed by the contact of two square semi-infinite lattices with single-band and two-band spectra, were obtained in the tight-binding approximation by the Green’s function method. The semi-elliptical density of states was used for numerical estimates, and the model of two interacting dimers was proposed to estimate the charge transfer. Application of this approach to description of lateral epitaxial and graphene-like heterostructures is discussed.

scholarly journals Низкоразмерные структуры карбида кремния: аналитические оценки характеристик электронного спектра

2020 ◽  
Vol 54 (5) ◽  
pp. 446
Author(s):  
С.Ю. Давыдов
Keyword(s):  
Silicon Carbide ◽  
Electronic Structure ◽  
Function Method ◽  
Tight Binding ◽  
Band Gaps ◽  
Tight Binding Approximation ◽  
One Dimensional ◽  
Dielectric Substrates ◽  
Effective Masses ◽  
Analytical Expressions

Abstract Using the Green’s function method within the tight-binding approximation, the electronic structure of an infinite silicon-carbide sheet, and nanoribbons and one-dimensional chains cut from it, is considered. Analytical expressions for band gaps, electron effective masses and characteristic velocities are derived. The effect of metal and dielectric substrates on the band characteristics is discussed.

scholarly journals Эпитаксиальный карбин: аналитические результаты

2019 ◽  
Vol 53 (7) ◽  
pp. 971
Author(s):  
С.Ю. Давыдов
Keyword(s):  
Density Wave ◽  
Tight Binding ◽  
Coulomb Repulsion ◽  
Free Standing ◽  
Tight Binding Approximation ◽  
Structural Modifications ◽  
Densities Of States ◽  
Semiconductor Substrates ◽  
A Charge ◽  
Analytical Expressions

AbstractThe Green’s function method in the tight-binding approximation is used to obtain analytical expressions for the electronic spectra and densities of states for two carbyne structural modifications (cumulene and polyyne). Metal and semiconductor substrates are considered and charge-transfer estimates are deduced. Criteria for the occurrence of a charge-density wave in free-standing and epitaxial carbynes are proposed taking into account the intra- and interatomic Coulomb repulsion. Analytical expressions for the phonon spectrum of free-standing carbyne are presented. The data obtained are compared with the results of numerical calculations performed by other researchers.

scholarly journals О декорировании зигзагообразных краев наноленты эпитаксиального графена

2019 ◽  
Vol 61 (3) ◽  
pp. 610
Author(s):  
С.Ю. Давыдов
Keyword(s):  
Density Of States ◽  
Tight Binding ◽  
Free State ◽  
Band Spectrum ◽  
Adsorption Complex ◽  
Chain Model ◽  
Double Chain ◽  
Occupation Numbers ◽  
A Chain ◽  
Analytical Expressions

AbstractA double-chain model of an epitaxial graphene nanoribbon, the zigzag edges of which are decorated with foreign adparticles, has been proposed. The substrate is assumed to be a metal. Analytical expressions for the Green’s functions of carbon adatoms and adparticles are obtained. The band spectrum for the free state is determined, and the approximation of the density of states is proposed. Analytical expressions for the occupation numbers in the mode of tight binding between the adsorption complex and the substrate are presented. A chain of carbon adatoms decorated with adparticles (epicarbyne) is considered.

scholarly journals К модельному описанию электронного спектра графеноподобных Янус-структур

2022 ◽  
Vol 64 (2) ◽  
pp. 277
Author(s):  
С.Ю. Давыдов
Keyword(s):  
Electronic Spectra ◽  
Function Method ◽  
Hexagonal Lattice ◽  
Tight Binding ◽  
Mechanical Deformation ◽  
Two Dimensional ◽  
Binding Theory ◽  
Effective Masses ◽  
Magnetic States ◽  
Analytical Expressions

Model of C – AB – D Janus structure as the compound formed by the interacting through atoms А and В dimers А – С and В – D, where А and В atoms are in the sites of two-dimensional hexagonal lattice and C and D atoms are on the opposite sides from AB list is proposed. In the scope of tight-binding theory and Green’s function method general equation for the dispersion low is obtained. The particular cases of C – AА – D и А – AB – В compounds are considered and analytical expressions for their electronic spectra is fulfilled. The effect of the external mechanical deformation on the band parameters including effective masses is examined. Problem of the magnetic states in Janus compounds is discussed.

A Tight Binding Model for the Density of States of Graphite-like Structures, Calculated using Green's Functions

1993 ◽  
Vol 46 (5) ◽  
pp. 601 ◽  
Author(s):  
BA McKinnon ◽  
TC Choy
Keyword(s):  
Electronic Structure ◽  
Carbon Fibre ◽  
Density Of States ◽  
Tight Binding ◽  
Analytic Solutions ◽  
Elliptic Integrals ◽  
Experimental Measurements ◽  
Tight Binding Model ◽  
Binding Model ◽  
Densities Of States

The electronic structure of graphite-like materials is investigated within the framework of the tight binding model. The densities of states of simple hexagonal and Bernal graphite are calculated, induding two layer (2D) and bulk (3D) cases. The calculation employs Green's function techniques, resulting in essentially analytic solutions in terms of elliptic integrals. The Bernal density of states is found to agree qualitatively with experimental measurements and the extension of our studies to surface effects and carbon fibre structures is also discussed.

LOCAL ELECTRONIC STRUCTURE OF Tl2Ca2Ba2Cu3O10 AND COMPARISON WITH LA-OXIDES AND Y-OXIDES

1990 ◽  
Vol 04 (09) ◽  
pp. 1537-1549 ◽  
Author(s):  
HUAI-YU WANG ◽  
FU-SUI LIU ◽  
EN-GE WANG ◽  
CHONG-YU WANG
Keyword(s):  
Electronic Structure ◽  
Nearest Neighbor ◽  
Tight Binding ◽  
The Other ◽  
Tight Binding Approximation ◽  
Densities Of States ◽  
Local Electronic Structure ◽  
Electronic Densities

Local electronic densities of states of Tl 2 Ca 2 Ba 2 Cu 3 O 10 (2223) are calculated by tight-binding approximation. The nearest and the next-nearest neighbor transitions are considered, and the results are compared with each other. After the latter is considered, the densities of states are smoothened and the semiconductor-like characteristic of the Tl-O layers disappears. Through comparison of 2223 with the other two high Tc ceramics La 2−x Sr x CuO 4 and YBa 2 Cu 3 O 7−x, it is believed that they have the same leading superconductive mechanism besides inter-plane interactions.

scholarly journals On the Energy Gaps Induced by a Semiconducting Substrate in the Graphene Density of States

2015 ◽  
Vol 9 (12) ◽  
pp. 234
Author(s):  
Sergey Yurevich Davydov ◽  
Alexander Alexandrovich Lebedev
Keyword(s):  
Electronic Spectrum ◽  
Density Of States ◽  
Energy Gap ◽  
Epitaxial Graphene ◽  
Energy Gaps ◽  
Densities Of States ◽  
Analytical Expressions ◽  
Semiconducting Substrate ◽  
Numerical Estimations

<p class="zhengwen"><span lang="EN-GB">The analytical expressions for the densities of states for graphene formed on semiconducting substrates are obtained. The problem on the induced gap is studied thoroughly. It is shown, that graphene electronic spectrum according to the relation between the system’s parameters can contain two gaps or one gap, overlapping with the energy gap of substrate. The gaps width dependences on the coupling regimes (tight and weak) are obtained. Numerical estimations are fulfilled for the epitaxial graphene on 6H-SiC{0001}.</span></p>

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