Electronic structure based on the local atomic environment for tight-binding bands

Haydock, Roger; Heine, Volker; Kelly, M. J.

doi:10.1088/0022-3719/5/20/004

Cited by 1,104 publications

(487 citation statements)

References 16 publications

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“…͑1͒ is a local density of state which is calculated using a continued fraction technique. 33 This is the most time-consuming part of the calculations and involves ϳ10 3 operations with the Hamiltonian for the considered systems to resolve the closely lying energy bands. The convergence of the continued fraction scheme must be separately verified.…”

Section: A Real-space Kubo Methodsmentioning

confidence: 99%

Electronic transport through Si nanowires: Role of bulk and surface disorder

et al. 2006

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We calculate the resistance and mean free path in long metallic and semiconducting silicon nanowires (SiNWs) using two different numerical approaches: A real space Kubo method and a recursive Green's function method. We compare the two approaches and find that they are complementary: depending on the situation a preferable method can be identified. Several numerical results are presented to illustrate the relative merits of the two methods. Our calculations of relaxed atomic structures and their conductance properties are based on density functional theory without introducing adjustable parameters. Two specific models of disorder are considered: Un-passivated, surface reconstructed SiNWs are perturbed by random on-site (Anderson) disorder whereas defects in hydrogen passivated wires are introduced by randomly removed H atoms. The un-passivated wires are very sensitive to disorder in the surface whereas bulk disorder has almost no influence. For the passivated wires, the scattering by the hydrogen vacancies is strongly energy dependent and for relatively long SiNWs (L > 200 nm) the resistance changes from the Ohmic to the localization regime within a 0.1 eV shift of the Fermi energy. This high sensitivity might be used for sensor applications.

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Section: A Real-space Kubo Methodsmentioning

confidence: 99%

Electronic transport through Si nanowires: Role of bulk and surface disorder

et al. 2006

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“…The Lanczos method 36 (so called the Haydock-HeineKelly recursion method 37,38 ) is a commonly used approaches to calculate the ADOS in disorder systems. The essential idea of the recursion method is that the Hamiltonian matrix is expressed using a tridiagonal representation iteratively.…”

Section: B the Recursion Methodsmentioning

confidence: 99%

Average density of states in disordered graphene systems

Jing

et al. 2008

Phys. Rev. B

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In this paper, the average density of states (ADOS) with a binary alloy disorder in disordered graphene systems are calculated based on the recursion method. We observe an obvious resonant peak caused by interactions with surrounding impurities and an anti-resonance dip in ADOS curves near the Dirac point. We also find that the resonance energy (Er) and the dip position (ε dip ) are sensitive to the concentration of disorders (x) and their on-site potentials (v). An linear relation, ε dip =xv, not only holds when the impurity concentration is low but this relation can be further extended to high impurity concentration regime with certain constraints. We also calculate the ADOS with a finite density of vacancies and compare our results with the previous theoretical results.

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“…27 In order to allow the treatment of large systems, the scheme uses a recursion method to construct a Lanzcos basis and then compute the cross section as a continued fraction. 28,29 The XANES spectrum is calculated in the electric dipole approximation, using the same first-principles total energy code as the one used for the structural relaxation. It was carried out in the relaxed 2×2×2 supercell (i.e 112 atoms), which contains one Cr atom and results from ab initio energy minimization mentioned in the previous subsection.…”

Section: Xanes Simulationsmentioning

confidence: 99%

Structural relaxation around substitutionalCr3+inMgAl2O4
Juhin
¹
,
Calas
²
,
Cabaret
³

et al. 2007
Phys. Rev. B
55
1
34
0
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The structural environment of substitutional Cr 3+ ion in MgAl2O4 spinel has been investigated by Cr K-edge Extended X-ray Absorption Fine Structure (EXAFS) and X-ray Absorption Near Edge Structure (XANES) spectroscopies. First-principles computations of the structural relaxation and of the XANES spectrum have been performed, with a good agreement to the experiment. The Cr-O distance is close to that in MgCr2O4, indicating a full relaxation of the first neighbors, and the second shell of Al atoms relaxes partially. These observations demonstrate that Vegard's law is not obeyed in the MgAl2O4-MgCr2O4 solid solution. Despite some angular site distortion, the local D 3d symmetry of the B-site of the spinel structure is retained during the substitution of Cr for Al. Here, we show that the relaxation is accomodated by strain-induced bond buckling, with angular tilts of the Mg-centred tetrahedra around the Cr-centred octahedron. By contrast, there is no significant alteration of the angles between the edge-sharing octahedra, which build chains aligned along the three four-fold axes of the cubic structure.

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Electronic structure based on the local atomic environment for tight-binding bands

Cited by 1,104 publications

References 16 publications

Electronic transport through Si nanowires: Role of bulk and surface disorder

Electronic transport through Si nanowires: Role of bulk and surface disorder

Average density of states in disordered graphene systems

Structural relaxation around substitutionalCr3+inMgAl2O4
Juhin
¹
,
Calas
²
,
Cabaret
³

et al. 2007
Phys. Rev. B
55
1
34
0
View full text Add to dashboard Cite

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Electronic structure based on the local atomic environment for tight-binding bands

Cited by 1,104 publications

References 16 publications

Electronic transport through Si nanowires: Role of bulk and surface disorder

Electronic transport through Si nanowires: Role of bulk and surface disorder

Average density of states in disordered graphene systems

Structural relaxation around substitutionalCr3+inMgAl2O4Juhin1, Calas2, Cabaret3 et al. 2007Phys. Rev. B551340View full textAdd to dashboardCite

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Structural relaxation around substitutionalCr3+inMgAl2O4
Juhin
¹
,
Calas
²
,
Cabaret
³

et al. 2007
Phys. Rev. B
55
1
34
0
View full text Add to dashboard Cite