Analysis of the structure of the surface local density of states at the Fermi level: an application of the surface Green function matching method

1989 ◽  
Vol 67 (9) ◽  
pp. 841-844 ◽  
Author(s):  
R. Baquero ◽  
L. Quiroga ◽  
A. Camacho
Keyword(s):  
Charge Transfer ◽  
Local Density ◽  
Tight Binding ◽  
Ferromagnetic Behavior ◽  
Local Density Of States ◽  
Matching Method ◽  
Full Agreement ◽  
Surface Band ◽  
Surface Green Function ◽  
Theory And Experiment

We use a tight-binding description of the bands of bulk vanadium to set a surface-band structure. We show that knowledge of the s–d charge transfer in the surface layer is very important to be able to reproduce the ferromagnetic behavior of the (100) vanadium surface. We use the surface Stoner criterion of Allan to determine the acceptable values for the s–d charge transfer. There is no full agreement between theory and experiment on the magnetic properties of (100) vanadium at present.

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.

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.

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.

scholarly journals Electronic Structure of Substitutionally Disordered Alloys: Direct Configurational Averaging

1992 ◽  
Vol 278 ◽  
Author(s):  
C. Wolverton ◽  
D. De Fontaine ◽  
H. Dreysse ◽  
G. Ceder
Keyword(s):  
Electronic Structure ◽  
Band Structure ◽  
Local Density ◽  
Tight Binding ◽  
Ternary Alloys ◽  
Orbital Method ◽  
Thermodynamic Quantities ◽  
Local Density Of States ◽  
Disordered Alloys ◽  
Effective Cluster

AbstractThe method of direct configurational averaging (DCA) has been proposed to study the electronic structure of disordered alloys. Local density of states and band structure energies are obtained by averaging over a small number of configrations within a tight-binding Hamiltonian. Effective cluster interactions, the driving quantities for ordering in solids, are computed for various alloys using a tight-binding form of the linearized muffin-tin orbital method (TB-LMTO). The DCA calculations are used to determine various energetic and thermodynamic quantities for binary and ternary alloys.

Modeling Optical Properties of Small Metallic Nanoparticles Based on Density Functional Theory

2007 ◽  
Author(s):  
Yi He ◽  
Taofang Zeng
Keyword(s):  
Optical Properties ◽  
Metallic Nanoparticles ◽  
Density Functional ◽  
Local Density ◽  
Incident Light ◽  
Tight Binding ◽  
Local Density Of States ◽  
Functional Theory ◽  
Hamilton Matrix ◽  
Different Diameters

Optical properties of silver nanoparticles with different diameters are investigated based on the electronic structures of component silver atoms. Within the frame of tight binding method, the local density of states of each silver atom is obtained through a recursive approach that extracts the required information directly from the Hamilton matrix. Then the interaction between the electric field of incident light and electrons in the nanoparticles is simulated to characterize their optical features and the size effects were interpreted according the results.

Effects of Structural Disorder on the Electronic Properties of Silicon: Tight-Binding Calculations of Grain Boundaries

1993 ◽  
Vol 297 ◽  
Author(s):  
M. Kohyama ◽  
R. Yamamoto
Keyword(s):  
Band Gap ◽  
Electronic Properties ◽  
Local Density ◽  
Tight Binding ◽  
Structural Disorder ◽  
Local Density Of States ◽  
Deep State ◽  
Amorphous Si ◽  
Semi Empirical ◽  
Twist Boundaries

The atomic and electronic structures of tilt and twist boundaries in Si have been calculated by using the transferable semi-empirical tight-binding (SETB) method, and the relations between the local structural disorder and the electronic properties of Si have been obtained clearly. The odd-membered rings and the four-membered rings induce the changes of the shape of the local density of states (LDOS). The bond distortions generate the peaks at the band edges in the LDOS, and greatly distorted bonds induce the weak-bond states inside the band gap. The three-coordinated defect generates a deep state in the band gap, which is much localized at the three-coordinated atom. The five-coordinated defect generates both deep and shallow states. The deep state is localized in the neighboring atoms except the five-coordinated atom, although the shallow states exist among the five-coordinated atom and the neighboring atoms. Configurations of boundaries are very effective in order to clarify the effects of the local structural disorder in amorphous SI.

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.

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