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.

Structural Disorder and Localized Gap States in Silicon Grain Boundaries from a Tight-Binding Model

1997 ◽  
Vol 491 ◽  
Author(s):  
F. Cleri ◽  
P. Keblinski ◽  
L. Colombo ◽  
S. R. Phillpot ◽  
D. Wolf
Keyword(s):  
Molecular Dynamics ◽  
Grain Boundaries ◽  
Tight Binding ◽  
Structural Disorder ◽  
High Energy ◽  
Tight Binding Model ◽  
Binding Model ◽  
Dynamics Simulations ◽  
Gap States ◽  
Forbidden Gap

ABSTRACTTight-binding molecular dynamics simulations of typical high-energy grain boundaries in silicon show that the atomic structure of the interface in thermodynamic equilibrium is similar to that of bulk amorphous silicon and contains coordination defects. The corresponding electronic structure is also amorphous-like, displaying extra states in the forbidden gap mainly localized around the coordination defects, where large changes in the bond-hybridization character are observed. It is proposed that such coordination defects in disordered high-energy grain boundaries are responsible for the experimentally observed gap states in polycrystalline Si.

Electronic Theory of Gettering and Passivation of Impurities in Semiconductors

1992 ◽  
Vol 262 ◽  
Author(s):  
K. Masuda-Jindo
Keyword(s):  
Tight Binding ◽  
Lattice Defects ◽  
Recursion Method ◽  
Impurity Atoms ◽  
Metal Impurities ◽  
Electronic Theory ◽  
Simple Physical Interpretation ◽  
Systematic Understanding ◽  
Gap States ◽  
Light Impurities

ABSTRACTWe calculate the interaction (segregation) energies Egegr between the extended lattice defects (dislocations and grain boundaries) and impurity atoms in semiconductors by using a microscopic electronic theory. In particular, we use the tight-binding recursion method coupled to the generalized zeros-and poles method and investigate the interaction between the extended lattice defects and various kinds of the impurity atoms in semiconductors (Si). For the systematic understanding of the impurity gettering, we consider a wide variety of impurities, both sp-valence and transition metal impurities, Ti, V, Cr, Mn, Fe, Co, Ni and Cu. We will show that the variation of the gap states plays an important role in determining the interaction energy Esegr between the impurity atom and the extended lattice defects- We also discuss the passivation of the extended lattice defects by interstitial light impurities like hydrogen in Si crystal, we present a simple physical interpretation of the impurity gettering and passivation in semiconductors.

Complex Defects in GaAs and GaP

1982 ◽  
Vol 14 ◽  
Author(s):  
P. J. Lin-Chung
Keyword(s):  
Electronic States ◽  
Group Iv ◽  
Experimental Results ◽  
Large Cluster ◽  
Defect Level ◽  
Defect Complexes ◽  
Densities Of States ◽  
Local Densities ◽  
Defect Levels ◽  
Gap States

ABSTRACTA study of the electronic states associated with divacancy defects and with the defect complexes involving an anion antisite with a group IV atom (Ac-IV) in GaAs and GaP is reported. The local densities of states have been determined using the large cluster recursion approach. The properties as well as the position of the gap states of the divacancy defect in GaAs are found to be consistent with the experimental results for the EL2 level. The change of the position of the defect levels of (Ac-IV) as a result of the change of bonding is analyzed. The effect of GaAs-A&As interface on the (Ac-IV) defect level is also examined.

Interplay Between Local Environment Effect and Electronic Structure Properties in Close Packed Structures

1990 ◽  
Vol 206 ◽  
Author(s):  
P. E. A. Turchi
Keyword(s):  
Tight Binding ◽  
Local Environment ◽  
Environment Effect ◽  
Crystalline Structures ◽  
Tcp Phases ◽  
Densities Of States ◽  
Valence Electrons ◽  
Local Densities ◽  
The Common ◽  
Fifth Order

ABSTRACTWithin a tight binding framework, the interplay between local atomic arrangement, orbital directionality and phase stability properties is discussed for a series of tetrahedrally close packed (tcp) structures. The common features which characterize the local densities of states of tcp phases can be explained by a moment analysis up to fourth order terms. On the contrary, it is shown that structural energy differences between simple and tcp crystalline structures requires the knowledge of at least the fifth order moments, a fact which has been underestimated in the past. Finally, the relative stability of various representative geometries, including the ones of simple crystalline structures is examined as a function of the number of valence electrons.

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.

CALCULATION FOR A Cu(001) SURFACE WITH AN IMPURITY ATOM

1999 ◽  
Vol 13 (04) ◽  
pp. 389-396
Author(s):  
CHIH-KAI YANG
Keyword(s):  
Electronic Structure ◽  
Impurity Atom ◽  
Magnetic Moments ◽  
Tight Binding ◽  
Real Space ◽  
Structure Calculation ◽  
Spin Polarized ◽  
Densities Of States ◽  
Self Consistent ◽  
Local Densities

I use a self-consistent electronic structure calculation to study the system of Cu(001) that has an impurity atom replacing one of the surface Cu atoms. The calculation makes use of the tight-binding linear muffin-tin orbitals (TB-LMTO) and is carried out in real space. I am able to derive the spin-polarized local densities of states for the impurity Cr and Fe respectively, which have peaks below the Fermi level. Charge transfers between the impurities and their neighbors also result in different distributions of magnetic moments for the two impurity systems, with the Cr having approximately 0.5μ B and the Fe atom having a negligible magnetic moment.

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.

Robust and controllable electronic local transports in armchair silicene nanoribbons under a perpendicular electric field

2017 ◽  
Vol 31 (21) ◽  
pp. 1750146 ◽  
Author(s):  
Xiongwen Chen ◽  
Zhengang Shi ◽  
Baoju Chen ◽  
Kehui Song
Keyword(s):  
Electric Field ◽  
Graphene Nanoribbons ◽  
Tight Binding ◽  
Structural Defects ◽  
Tight Binding Approximation ◽  
Current Switch ◽  
Densities Of States ◽  
Silicene Nanoribbons ◽  
Local Densities ◽  
Transport Channels

We study the electronic local distribution and transports in pristine armchair-edge silicene nanoribbons (ASiNRs) based on the tight-binding approximation. By calculating the local densities of states at different sites and the bond current between two adjacent sites, we show that comparing to the pristine armchair-edge graphene nanoribbons, a similar “[Formula: see text]” rule and multiple low-electron transport channels exist in the pristine [Formula: see text]-ASiNRs. However, differently, they are controllable to appear and disappear by applying an electric field perpendicular to the ribbon plane. Therefore, one can manipulate the semiconducting channels and realize the current switch “on/off,” unchanging their structures. Moreover, the results are robust against the edge-passivation and a few structural defects, which ensures their stability for the practical application in the silicene-based device.

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