scholarly journals Точно решаемая модель графеновой наноленты с зигзагообразными краями

2020 ◽  
Vol 54 (2) ◽  
pp. 170
Author(s):  
С.Ю. Давыдов ◽  
А.В. Зубов
Keyword(s):  
Structural Model ◽  
Graphene Nanoribbon ◽  
Zigzag Edge ◽  
Occupation Numbers ◽  
Densities Of States ◽  
Local Densities ◽  
Analytical Expressions

Abstract Exact analytical expressions for the local densities of states and the occupation numbers of atoms at the zigzag edge of a graphene nanoribbon are derived in the context of a simple structural model. As an example of application of the results, the problem of a Koster–Slater defect is considered.

scholarly journals Цепочечная модель декорирования зигзагообразной кромки графена

2019 ◽  
Vol 53 (1) ◽  
pp. 83
Author(s):  
С.Ю. Давыдов
Keyword(s):  
Energy Band ◽  
Structural Model ◽  
Metal Substrate ◽  
Band Spectrum ◽  
Brick Wall ◽  
Zigzag Edge ◽  
Occupation Numbers ◽  
Graphene Lattice ◽  
Densities Of States ◽  
Analytical Expressions

AbstractFor a brick-wall-like lattice topologically equivalent to the graphene lattice, a simple structural model of a zigzag edge decorated with particles is constructed. Analytical expressions for the energy band spectrum, densities of states, and occupation numbers of the graphene–particles system are derived for a system in the free state and for a system formed on a metal substrate.

scholarly journals О декорировании зигзагообразной кромки эпитаксиального графена

2019 ◽  
Vol 61 (1) ◽  
pp. 186
Author(s):  
С.Ю. Давыдов
Keyword(s):  
Electronic Structure ◽  
Graphene Sheet ◽  
Cluster Model ◽  
Dipole Interaction ◽  
Metal Substrate ◽  
Zigzag Edge ◽  
Occupation Numbers ◽  
Local Densities ◽  
Analytical Expressions

AbstractTwo approaches are proposed to the problem of the coupling of adsorbed particles with atoms of a zigzag edge of graphene formed on a metal substrate. The first approach is based on the Kalkstein and Soven scheme, which makes it possible to determine the electronic structure of a semi-infinite graphene sheet. The second approach is based on a cluster model of a zigzag edge. Analytical expressions are obtained for the local densities of the system’s states and the occupation numbers of a carbon adatom and an adparticle. The case of an isolated adparticle is considered in detail, and a method of taking into account the dipole–dipole interaction of particles aligned along the edge is proposed.

scholarly journals Цепочечная модель зигзагообразного контакта латеральных графеноподобных гетероструктур

2018 ◽  
Vol 44 (21) ◽  
pp. 55
Author(s):  
С.Ю. Давыдов
Keyword(s):  
Boron Nitride ◽  
Density Of States ◽  
Structural Model ◽  
Hexagonal Boron Nitride ◽  
Two Dimensional ◽  
Occupation Numbers ◽  
Densities Of States ◽  
Spectrum Density ◽  
Analytical Expressions ◽  
Good Agreement

AbstractA simple structural model is proposed for the zigzag interface formed by contacting two-dimensional graphene-like compounds AB and CD (both free and formed on a metal). For the graphene–hexagonal boron nitride system, analytical expressions for the electron spectrum, density of states, and atom occupation numbers at the interface are obtained. The results of calculating the densities of states and occupation numbers within two alternative approximations are in good agreement.

scholarly journals Кластерная модель латеральной графеноподобной гетероструктуры: оценки перехода заряда

2018 ◽  
Vol 60 (9) ◽  
pp. 1815
Author(s):  
С.Ю. Давыдов
Keyword(s):  
Charge Transfer ◽  
Boron Nitride ◽  
Cluster Model ◽  
Binary Compound ◽  
Metal Substrate ◽  
Two Dimensional ◽  
Occupation Numbers ◽  
Densities Of States ◽  
Local Densities ◽  
Analytical Expressions

AbstractA simple cluster model is proposed to describe zigzag and armchair contacts of graphene to a hexagonal two-dimensional binary compound adsorbed on a metal substrate. A graphene–boron nitride heterostructure (HS) is studied in detail. Analytical expressions are obtained for the local densities of states and the occupation numbers of contact atoms. The charge transfer for quasi-free HSs is analyzed. The energy of binding of a HS to a metal substrate is estimated.

scholarly journals О магнитных состояниях зигзагообразной кромки графеновой наноленты

2020 ◽  
Vol 62 (1) ◽  
pp. 180
Author(s):  
С.Ю. Давыдов
Keyword(s):  
Electronic Structure ◽  
Density Of States ◽  
Structural Model ◽  
Magnetic Moments ◽  
Nearest Neighbors ◽  
Metal Substrate ◽  
Band Spectrum ◽  
Zigzag Edge ◽  
Anderson Hamiltonian ◽  
Occupation Numbers

Abstract Using a simple structural model and the multicenter Anderson Hamiltonian, Green’s functions are obtained for the atoms of the zigzag edge of an epitaxial graphene nanoribbon. The electronic structure of the free nanoribbon is discussed in detail. Specifically, expressions for the band spectrum and density of states are found and estimates of the occupation numbers and magnetic moments are given. For a nanoribbon strongly bonded to a metal substrate, the criteria for the appearance of magnetic moments are determined. As it is shown for both free and epitaxial nanoribbons, the probability of the appearance of magnetic moments and their magnitude for zigzag edge atoms that have two nearest neighbors is higher than for atoms with three nearest neighbors.

scholarly journals APPLICATIONS OF DENSITY MATRICES IN A TRAPPED BOSE GAS

2006 ◽  
Vol 20 (15) ◽  
pp. 2189-2221 ◽  
Author(s):  
K. CH. CHATZISAVVAS ◽  
S. E. MASSEN ◽  
CH. C. MOUSTAKIDIS ◽  
C. P. PANOS
Keyword(s):  
Quantum Information ◽  
Bose Gas ◽  
Einstein Condensation ◽  
Density Distributions ◽  
Occupation Numbers ◽  
The One ◽  
Bose Einstein ◽  
Jensen Shannon Divergence ◽  
Analytical Expressions ◽  
Short Range Correlations

An overview of the Bose–Einstein condensation of correlated atoms in a trap is presented by examining the effect of interparticle correlations to one- and two-body properties of the above systems at zero temperature in the framework of the lowest order cluster expansion. Analytical expressions for the one- and two-body properties of the Bose gas are derived using Jastrow-type correlation function. In addition numerical calculations of the natural orbitals and natural occupation numbers are also carried out. Special effort is devoted for the calculation of various quantum information properties including Shannon entropy, Onicescu informational energy, Kullback–Leibler relative entropy and the recently proposed Jensen–Shannon divergence entropy. The above quantities are calculated for the trapped Bose gases by comparing the correlated and uncorrelated cases as a function of the strength of the short-range correlations. The Gross–Piatevskii equation is solved, giving the density distributions in position and momentum space, which are employed to calculate quantum information properties of the Bose gas.

Commentary on local densities of states, surface bonds and rate processes

1986 ◽  
Vol 318 (1541) ◽  
pp. 135-139 ◽  
Keyword(s):  
Electron Spectroscopy ◽  
Main Part ◽  
Catalytic Reactions ◽  
Solid Surfaces ◽  
Densities Of States ◽  
Rate Processes ◽  
Local Densities ◽  
Structure And Bonding ◽  
The Many

Although the main part of the title of this meeting is ‘ Studies of the surfaces of solids by electron spectroscopy’, the papers presented also cover some of the wider aspects of these studies, and I wish to pursue some of these here. I remark first that most of the systems studied by surface-sensitive spectroscopies are not technologically important, or even interesting in their own right. What makes them important and interesting is that the solids studied are, or are related to, catalysts, and the adsorbates studied are reactants, products or intermediates in important catalytic reactions. Consequently I ask the question: what is the relevance to catalysis of studies of structure, and bonding at solid surfaces? From among the many answers that might be given, I select two.

Electronic Structure of Epitaxial SiO2/Si(100) Interfaces

1989 ◽  
Vol 159 ◽  
Author(s):  
T. Motooka
Keyword(s):  
Tight Binding ◽  
Interface States ◽  
Photoelectron Spectra ◽  
Band Spectrum ◽  
Binding Model ◽  
Initial Oxidation ◽  
Recursion Method ◽  
Densities Of States ◽  
Local Densities ◽  
Gap States

ABSTRACTThe local densities of states (LDOS) of epitaxial SiO, layers on Si(100) surfaces have been calculated using the recursion method combined with the Harrison's universal tight-binding model. The interface states associated with strained epitaxial layers of β-cristobalite (√2×√2)R45° and tridymite (1010)<0001> || Si(100)<011> were examined. In the β-cristobalite layer, gap states due to the surface Si dangling bonds appeared while they were eliminated by H termination. In the tridymite layer, the interface states primarily composed of the surface Si back bonds appeared near the Si conduction band minimum. Comparing the calculated DOS with photoelectron spectra for initial oxidation processes of clean Si(100), it was found that the valence band spectrum from the initial oxide formed at ∼300°C resembled that of the β-cristobalite layer.

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