scholarly journals Tunneling conductance and local density of states in tight-binding junctions

2011 ◽  
Vol 84 (15) ◽  
Author(s):  
C. Berthod ◽  
T. Giamarchi
Keyword(s):  
Density Of States ◽  
Local Density ◽  
Tight Binding ◽  
Tunneling Conductance ◽  
Local Density Of States

ENERGY GAP DEPENDENCE ON ANION CONCENTRATION FOR GaxIn1-xAsyP1-y QUATERNARY ALLOY BY RECURSION METHOD

2004 ◽  
Vol 18 (18) ◽  
pp. 955-962
Author(s):  
MUSA EL-HASAN ◽  
REZEK ESTATIEH
Keyword(s):  
Density Of States ◽  
Energy Gap ◽  
Local Density ◽  
Tight Binding ◽  
Quaternary Alloy ◽  
Average Density ◽  
Local Density Of States ◽  
Recursion Method ◽  
Orbital Decomposition ◽  
Lattice Matched

Three terminators have been tested, square root terminator, quadreture terminator and linear terminator, it was found that the linear terminator is the best, so it was used in calculating local density of states (LDOS) and it's orbital decomposition, alloy average density of states, and energy gap for different anion concentrations for InP lattice matched alloy. The results were compared with our previous calculations of (LDOS), and results from other methods. Energy gap was compared with experimental measurements. A five orbital sp3s* per atom model was used in the tight-binding representation of the Hamiltonian.

Electronic band structure of silver low-index surfaces: a tight-binding study

2020 ◽  
Vol 98 (5) ◽  
pp. 488-496
Author(s):  
H.J. Herrera-Suárez ◽  
A. Rubio-Ponce ◽  
D. Olguín
Keyword(s):  
Band Structure ◽  
Density Of States ◽  
Electronic Band Structure ◽  
Local Density ◽  
Tight Binding ◽  
Theoretical Data ◽  
Binding Study ◽  
Local Density Of States ◽  
Electronic Band ◽  
Tight Binding Method

We studied the electronic band structure and corresponding local density of states of low-index fcc Ag surfaces (100), (110), and (111) by using the empirical tight-binding method in the framework of the Surface Green’s Function Matching formalism. The energy values for different surface and resonance states are reported and a comparison with the available experimental and theoretical data is also done.

ELECTRONIC LOCAL DENSITY OF STATES FOR THE TiNi(001) SURFACE

1999 ◽  
Vol 06 (05) ◽  
pp. 719-723 ◽  
Author(s):  
G. CANTO ◽  
R. DE COSS ◽  
D. A. PAPACONSTANTOPOULOS
Keyword(s):  
Surface Layer ◽  
Density Of States ◽  
Local Density ◽  
Tight Binding ◽  
First Principles Calculations ◽  
Local Density Of States ◽  
A Value ◽  
Atomic Surface ◽  
Surface Green Function ◽  
B2 Structure

We present a self-consistent tight-binding calculation of the electronic structure for the (001) surface of TiNi in the CsCl (B2) structure. The results were obtained using a three-center s–p–d orthogonal tight-binding Hamiltonian fitted to first-principles calculations, within the surface Green function matching formalism. We have analyzed the local density of states (LDOS) for cases with Ni or Ti at the surface layer. For the case where Ni is at the atomic surface layer we find that the corresponding LDOS consists predominantly of bonding states, like in the bulk but with a value at EF reduced by 38% with respect to the bulk; for this surface a strong peak in the LDOS was found at -1.4 eV below EF. For the case where Ti is at the atomic surface layer the corresponding LDOS consists mainly of antibonding states, but with a value at EF higher than in the bulk by 30%. Comparatively, the case where Ni is at the surface layer presents lower values of LDOS at EF and d holes with respect to the case where Ti is at the surface layer, and therefore more chemical activity can be expected for the Ti surface.

scholarly journals ELECTRONIC STATES AND LOCAL DENSITY OF STATES NEAR GRAPHENE CORNER EDGE

2012 ◽  
Vol 11 ◽  
pp. 151-156 ◽  
Author(s):  
YUJI SHIMOMURA ◽  
YOSITAKE TAKANE ◽  
KATSUNORI WAKABAYASHI
Keyword(s):  
Density Of States ◽  
Nearest Neighbor ◽  
Local Density ◽  
Tight Binding ◽  
Localized States ◽  
Destructive Interference ◽  
Edge States ◽  
Local Density Of States ◽  
Binding Model ◽  
Recursion Method

We study that stability of edge localized states in semi-infinite graphene with a corner edge of the angles 60°, 90°, 120° and 150°. We adopt a nearest-neighbor tight-binding model to calculate the local density of states (LDOS) near each corner edge using Haydock's recursion method. The results of the LDOS indicate that the edge localized states stably exist near the 60°, 90°, and 150° corner, but locally disappear near the 120° corner. By constructing wave functions for a graphene ribbon with three 120° corners, we show that the local disappearance of the LDOS is caused by destructive interference of edge states and evanescent waves.

ELECTRONIC STRUCTURE OF STRAINED VANADIUM OVERLAYERS ON W(100) AND Ta(100)

1996 ◽  
Vol 03 (04) ◽  
pp. 1505-1509 ◽  
Author(s):  
R. DE COSS
Keyword(s):  
Electronic Structure ◽  
Density Of States ◽  
Lattice Mismatch ◽  
Local Density ◽  
Tight Binding ◽  
Local Density Of States ◽  
Tight Binding Approximation ◽  
Surface Electronic Structure ◽  
Topmost Layer ◽  
Surface Green Function

We study the role of hybridization and overlayer–substrate lattice mismatch in determining the surface electronic structure of strained V monolayers and bilayers on W(100) and Ta(100). The local density of states is calculated in the tight-binding approximation within the surface-Green-function-matching formalism. For one monolayer of V on W(100) and Ta(100), the strong monolayer–substrate 3d–5d hybridization determines the features of the surface local density of states, with essentially no differences between 1V/W(100) and 1V/Ta(100). For the bilayer we find that the electronic structure of the topmost layer depends strongly on the lattice mismatch between overlayer and substrate. In particular, we find that the surface local density of states at the Fermi level in 2V/Ta(100) is 69% higher than in 1V/Ta(100); the lattice mismatch between bulk constants of V and Ta is 9.0%. These results indicate that strain induces strong band narrowing in vanadium overlayers on transition metals, despite the large overlayer–substrate hybridization, but depends critically on the film thickness.

Effects of band hybridization on electronic properties in tuning armchair graphene nanoribbons

2016 ◽  
Vol 94 (2) ◽  
pp. 218-225 ◽  
Author(s):  
M. Khatun ◽  
Z. Kan ◽  
A. Cancio ◽  
C. Nelson
Keyword(s):  
Fermi Level ◽  
Density Of States ◽  
Graphene Nanoribbons ◽  
Local Density ◽  
Tight Binding ◽  
Edge States ◽  
Local Density Of States ◽  
Periodic Patterns ◽  
Armchair Graphene Nanoribbons ◽  
Armchair Graphene

We explore a model of armchair graphene nanoribbons tuned by functionalizing the edge states. Edge modifications are modeled by changing the electronic energy of the edge states in specific periodic patterns. The model can be considered to mimic a controlled doping process with different elements. The band structure, density of states, conductance, and local density of states are calculated, using the tight binding approach, Green’s function methodology, and the Landauer formula. The results show interesting behaviors, which are considerably different from the properties of the perfect nanoribbons. The hybridization of conducting bands with non-conducting bands, which appear perfectly flat in the perfect ribbon, opens up and modifies gaps in conductance near the Fermi level. One particular pattern of edge functionalization causes a strong, symmetric, and systematic band gap change about the Fermi level, modifying the electronic characteristics in the energy dispersion, density of states, local density of states, and conductance.

scholarly journals Electron Pumping and Spectral Density Dynamics in Energy-Gapped Topological Chains

2021 ◽  
Vol 11 (2) ◽  
pp. 772
Author(s):  
Marcin Kurzyna ◽  
Tomasz Kwapiński
Keyword(s):  
Density Of States ◽  
Energy Gap ◽  
Local Density ◽  
Tight Binding ◽  
Operator Technique ◽  
Local Density Of States ◽  
Effective Electron ◽  
Topological States ◽  
Electron Transport Properties ◽  
External Time

Electron pumping through energy-gapped systems is restricted for vanishing local density of states at the Fermi level. In this paper, we propose a topological Su–Schrieffer–Heeger (SSH) chain between unbiased leads as an effective electron pump. We analyze the electron transport properties of topologically trivial and nontrivial systems in the presence of external time-dependent forces in the form of one-Gaussian or two-Gaussian perturbations (train impulses). We have found that the topologically trivial chain stands for much better charge pump than other normal or nontrivial chains. It is important that, during the perturbation, electrons are pumped through the mid-gap temporary states or through the induced sidebands states outside the energy gap. We also analyze the local density of states dynamics during the quench transition between different topological phases of the SSH chain. It turns out that after the quench, the edge topological states migrate through other sites and can temporarily exist in a topologically trivial part of the system. The tight-binding Hamiltonian and the evolution operator technique are used in our calculations.

scholarly journals Supersymmetric Cluster Expansions and Applications to Random Schrödinger Operators

2021 ◽  
Vol 24 (1) ◽  
Author(s):  
Luca Fresta
Keyword(s):  
Density Of States ◽  
Local Density ◽  
Schrödinger Operators ◽  
Random Schrödinger Operators ◽  
Schrodinger Operators ◽  
Local Density Of States ◽  
Weak Disorder ◽  
Cluster Expansions ◽  
Strong Disorder ◽  
Lifshitz Tail

AbstractWe study discrete random Schrödinger operators via the supersymmetric formalism. We develop a cluster expansion that converges at both strong and weak disorder. We prove the exponential decay of the disorder-averaged Green’s function and the smoothness of the local density of states either at weak disorder and at energies in proximity of the unperturbed spectrum or at strong disorder and at any energy. As an application, we establish Lifshitz-tail-type estimates for the local density of states and thus localization at weak disorder.

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