scholarly journals Tight-binding Calculations of Band Structure and Conductance in Graphene Nano-ribbons

2009 ◽  
Vol 19 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Hoang Manh Tien ◽  
Nguyen Hai Chau ◽  
Phan Thi Kim Loan
Keyword(s):  
Band Structure ◽  
Electronic Properties ◽  
Nearest Neighbor ◽  
Graphene Nanoribbons ◽  
Tight Binding ◽  
Numerical Calculations ◽  
Dimensional System ◽  
Tight Binding Approximation ◽  
One Dimensional ◽  
Edge Conditions

We suggest a general approach based on the nearest-neighbor tight-binding approximation (TB) to investigate the band structure and conductance of a quasi-one dimensional system. Numerical calculations carried out for Graphene nanoribbons (GNRs) with different widths and edge conditions (zigzag and armchair) reveal the well-known results that the electronic properties of GNRs depend strongly on the size and geometry of the sample.

Empirical Tight-Binding Applied to Silicon Nanoclusters

1997 ◽  
Vol 491 ◽  
Author(s):  
G. Allan ◽  
C. Delerue ◽  
M. Lannoo
Keyword(s):  
Band Structure ◽  
Nearest Neighbor ◽  
Good Description ◽  
Tight Binding ◽  
Localized States ◽  
Basis Set ◽  
Band Structure Calculation ◽  
Minimal Basis ◽  
Tight Binding Approximation ◽  
Bulk Band

ABSTRACTThe calculation of the electronic structure of silicon nanostructures is used to discuss the accuracy of results obtained by the tight-binding method. We first show that the level of refinement of the tight-binding approximation must be adapted to the calculated property. For example, an accurate description of both the valence and conduction bands which can be achieved with a 3rd-nearest neighbor approximation is necessary to calculate the variation of the gap energy with the silicon crystallite size. The sp3s* model which gives a bad description of the conduction band underestimates the confinement energy but can give good results when it is used to determine the variation of the crystallite band gap with pressure. To study Si-III (BC-8) nanocrystallites, we show that a good description of the bulk band structure can be obtained with non-orthogonal tight-binding but due to the large number of nearest neighbors one must take analytical variations of the parameter with interatomic distances. The parameters involved in these expressions can be easily fitted to the bulk band structures using the k-point symmetry without requiring the use of group theory. Finally we discuss the effect of increasing the size of the minimal-basis set and we show that it would be possible to get the values of the tight-binding parameters from a first-principles localized states band structure calculation avoiding the fit to the energy dispersion curves.

BAND STRUCTURE OF RHOMBOHEDRAL GRAPHITE

1958 ◽  
Vol 36 (3) ◽  
pp. 352-362 ◽  
Author(s):  
R. R. Haering
Keyword(s):  
Band Structure ◽  
Fermi Surface ◽  
Nearest Neighbor ◽  
Tight Binding ◽  
Rhombohedral Structure ◽  
Hexagonal Prism ◽  
Exchange Integral ◽  
Tight Binding Approximation ◽  
Out Of Plane ◽  
Bernal Stacking

The band structure of rhombohedral graphite has been investigated using the nearest-neighbor tight-binding approximation. The resulting behavior of the π-bands near the Fermi surface is more complex than in the case of the Bernal stacking. The two π-bands still touch, but the touching points no longer lie on the edges of a hexagonal prism in k-space. Instead, they lie on cylinders whose axes are the edges of the hexagonal prism. The radii of these cylinders are proportional to γ1, the nearest "out-of-plane" exchange integral. The de Haas – Van Alphen effect in the rhombohedral structure may be expected to yield useful information about the magnitude of γ1.

scholarly journals Enhancement of thermoelectric figure of merit in zigzag graphene nanoribbons with periodic edge vacancies

2017 ◽  
Vol 31 (15) ◽  
pp. 1750124 ◽  
Author(s):  
D. V. Kolesnikov ◽  
O. G. Sadykova ◽  
V. A. Osipov
Keyword(s):  
Seebeck Coefficient ◽  
Figure Of Merit ◽  
Nearest Neighbor ◽  
Graphene Nanoribbons ◽  
Tight Binding ◽  
Dynamical Matrix ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
Tight Binding Approximation ◽  
Zigzag Graphene Nanoribbons

The influence of periodic edge vacancies and antidot arrays on the thermoelectric properties of zigzag graphene nanoribbons (ZGNRs) are investigated. Using Green’s function method, the tight-binding approximation for the electron Hamiltonian and the 4th nearest neighbor approximation for the phonon dynamical matrix, we calculate the Seebeck coefficient and the thermoelectric figure of merit. It is found that, at a certain periodic arrangement of vacancies on both edges of zigzag nanoribbon, a finite band gap opens and almost twofold degenerate energy levels appear. As a result, a marked increase in the Seebeck coefficient takes place. It is shown that an additional enhancement of the thermoelectric figure of merit can be achieved by a combination of periodic edge defects with an antidot array.

Electrical Transport Properties of Carbon Nanotube Metal-Semiconductor Heterojunction

2016 ◽  
Vol 15 (05n06) ◽  
pp. 1660009 ◽  
Author(s):  
Keka Talukdar ◽  
Anil Shantappa
Keyword(s):  
Electrical Transport ◽  
Nearest Neighbor ◽  
Electronic Devices ◽  
Tight Binding ◽  
Transmission Function ◽  
Topological Defects ◽  
Dynamics Simulation ◽  
Internal Stresses ◽  
Electrical Transport Properties ◽  
Tight Binding Approximation

Carbon nanotubes (CNTs) have been proved to have promising applicability in various fields of science and technology. Their fascinating mechanical, electrical, thermal, optical properties have caught the attention of today’s world. We have discussed here the great possibility of using CNTs in electronic devices. CNTs can be both metallic and semiconducting depending on their chirality. When two CNTs of different chirality are joined together via topological defects, they may acquire rectifying diode property. We have joined two tubes of different chiralities through circumferential Stone–Wales defects and calculated their density of states by nearest neighbor tight binding approximation. Transmission function is also calculated to analyze whether the junctions can be used as electronic devices. Different heterojunctions are modeled and analyzed in this study. Internal stresses in the heterojunctions are also calculated by molecular dynamics simulation.

scholarly journals Accurate six-band nearest-neighbor tight-binding model for the π-bands of bulk graphene and graphene nanoribbons

2011 ◽  
Vol 109 (10) ◽  
pp. 104304 ◽  
Author(s):  
Timothy B. Boykin ◽  
Mathieu Luisier ◽  
Gerhard Klimeck ◽  
Xueping Jiang ◽  
Neerav Kharche ◽  
...  
Keyword(s):  
Nearest Neighbor ◽  
Graphene Nanoribbons ◽  
Tight Binding ◽  
Tight Binding Model ◽  
Binding Model

EFFECTIVE MOBILITY MODEL OF GRAPHENE NANORIBBON IN PARABOLIC BAND ENERGY

2011 ◽  
Vol 25 (10) ◽  
pp. 739-745 ◽  
Author(s):  
N. A. AMIN ◽  
M. T. AHMADI ◽  
Z. JOHARI ◽  
S. M. MOUSAVI ◽  
R. ISMAIL
Keyword(s):  
Experimental Data ◽  
Band Structure ◽  
Transport Properties ◽  
Conventional Method ◽  
Dirac Point ◽  
Graphene Nanoribbons ◽  
Mobility Model ◽  
Band Energy ◽  
One Dimensional ◽  
Effective Mobility

In this letter, we investigate the transport properties of one-dimensional semiconducting Graphene nanoribbons (GNRs) with parabolic band structure near the Dirac point. The analytical model of effective mobility is developed by using the conductance approach, which differs from the conventional method of extracting the effective mobility using the well-known Matthiessen rule. Graphene nanoribbons conductance model developed was applied in the Drude model to obtain the effective mobility, which then gives nearly close comparison with the experimental data.

scholarly journals One-dimensional confinement and width-dependent bandgap formation in epitaxial graphene nanoribbons

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Hrag Karakachian ◽  
T. T. Nhung Nguyen ◽  
Johannes Aprojanz ◽  
Alexei A. Zakharov ◽  
Rositsa Yakimova ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Quantum Confinement ◽  
Field Effect Transistors ◽  
Graphene Nanoribbons ◽  
Tight Binding ◽  
Scanning Tunneling Spectroscopy ◽  
Scanning Tunneling ◽  
Pristine Graphene ◽  
One Dimensional ◽  
Experimental Findings

AbstractThe ability to define an off state in logic electronics is the key ingredient that is impossible to fulfill using a conventional pristine graphene layer, due to the absence of an electronic bandgap. For years, this property has been the missing element for incorporating graphene into next-generation field effect transistors. In this work, we grow high-quality armchair graphene nanoribbons on the sidewalls of 6H-SiC mesa structures. Angle-resolved photoelectron spectroscopy (ARPES) and scanning tunneling spectroscopy measurements reveal the development of a width-dependent semiconducting gap driven by quantum confinement effects. Furthermore, ARPES demonstrates an ideal one-dimensional electronic behavior that is realized in a graphene-based environment, consisting of well-resolved subbands, dispersing and non-dispersing along and across the ribbons respectively. Our experimental findings, coupled with theoretical tight-binding calculations, set the grounds for a deeper exploration of quantum confinement phenomena and may open intriguing avenues for new low-power electronics.

AGING IN A ONE-DIMENSIONAL EDWARDS–ANDERSON SPIN GLASS MODEL WITH LONG-RANGE INTERACTIONS

2003 ◽  
Vol 14 (03) ◽  
pp. 257-265 ◽  
Author(s):  
MARCELO A. MONTEMURRO ◽  
FRANCISCO A. TAMARIT
Keyword(s):  
Long Range ◽  
Nearest Neighbor ◽  
Dynamical Behavior ◽  
Mean Field ◽  
Dimensional System ◽  
One Dimensional ◽  
Long Range Interactions ◽  
Glass Model ◽  
The One ◽  
Aging Phenomena

In this work we study, by means of numerical simulations, the out-of-equilibrium dynamics of the one-dimensional Edwards–Anderson model with long-range interactions of the form ± Jr-α. In the limit α → 0 we recover the well known Sherrington–Kirkpatrick mean-field version of the model, which presents a very complex dynamical behavior. At the other extreme, for α → ∞ the model converges to the nearest-neighbor one-dimensional system. We focus our study on the dependence of the dynamics on the history of the sample (aging phenomena) for different values of α. The model is known to have mean-field exponents already for values of α = 2/3. Our results indicate that the crossover to the dynamic mean-field occurs at a value of α < 2/3.

BACKSCATTERING AND THE DECAY OF TRANSMITTANCE IN A COHERENTLY ABSORBING OR AMPLIFYING ORDERED CHAIN

1996 ◽  
Vol 10 (03n05) ◽  
pp. 125-132 ◽  
Author(s):  
ASOK K. SEN
Keyword(s):  
Quantum System ◽  
Electronic Properties ◽  
Recent Work ◽  
Active Medium ◽  
Open Quantum System ◽  
Tight Binding ◽  
One Dimensional ◽  
A Value ◽  
Closed Quantum System ◽  
Coherent Amplification

We study electronic properties of a one-dimensional, semi-infinite ordered chain in the presence of either absorption or amplification at each site (the site potentials having imaginary positive or negative parts) within a single-band, tight binding Hamiltonian. The spectrum in either case for an isolated (closed) quantum system becomes broader compared to the regular Bloch case. For an infinitely long ordered chain (open quantum system), the reflectance saturates to a value greater (lesser) than unity in the amplifying (absorbing) case and the transmittance decays to zero in either case. Thus, in contrast to a recent work of Pradhan and Kumar [Phys. Rev.B50, 9644 (1994)], it is not necessary to have any “synergy between wave confinement” due to any disorder or interaction induced confining mechanism on the transmitted wave and “coherent amplification by the active medium” to achieve an amplification in the reflectance.

Band structure of silicene in the tight binding approximation

2015 ◽  
Vol 121 (1) ◽  
pp. 115-121 ◽  
Author(s):  
A. V. Gert ◽  
M. O. Nestoklon ◽  
I. N. Yassievich
Keyword(s):  
Band Structure ◽  
Tight Binding ◽  
Tight Binding Approximation
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