Journal ArticleDOI
Analytic Properties of the Homomorphic Cluster Coherent Potential Approximation
Takashi Odagaki,Fumiko Yonezawa +1 more
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TLDR
In this paper, it was shown that the breakdown of analyticity is not found in average Green's functions which are obtained on the basis of the cluster coherent potential approximation for systems with substitutional disorder if the one particle total hamiltonian for a given configuration is expressed as a sum of homomorphic single-cluster hamiltonians.Abstract:
We show that the breakdown of analyticity is not found in average Green's functions which are obtained on the basis of the cluster coherent potential approximation for systems with substitutional disorder if the one particle total hamiltonian for a given configuration is expressed as a sum of homomorphic single-cluster hamiltonians. Disorder can be site-diagonal and/or off-diagonal. In this article the emphasis is laid on off-diagonal cases. We first treat three-dimensional disordered systems with a semielliptic distribution of nearest neighbour transfers { V i j }. We also apply our homomorphic cluster coherent approximation (HCPA) to the bond percolation problem; we obtain the densities of states which show characteristic features found through a computer simulation.read more
Citations
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Stochastic transport in disordered systems
TL;DR: In this paper, the authors developed a theory of stochastic transport in disordered media, starting from a linear master equation with random transition rates, and employed a Green function formalism to reduce the basic equation to a form suitable for the construction of a class of effective medium approximations (EMAs).
Journal ArticleDOI
Electron localisation in systems with purely off-diagonal randomness
TL;DR: In this paper, a homomorphic cluster CPA with the L(E) criterion was used to study localisation in a simple cubic lattice and a computer simulation was used for a square lattice with the participation-ratio criterion.
Journal ArticleDOI
Homomorphic Cluster Coherent Potential Approximation for Systems with Site-Diagonal and/or Off-Diagonal Randomness
Fumiko Yonezawa,Takashi Odagaki +1 more
TL;DR: In this article, the authors apply the homomorphic cluster coherent potential approximation (HCPA) to systems with site-diagonal and/or offdiagonal randomness, and show numerically that the average Green's function obtained on the basis of the HCPA is analytic off the real axis on the complex energy plane.
Journal ArticleDOI
Calculation of the exciton green's function of a molecular crystal from a two-site dynamical coherent potential approximation
TL;DR: In this article, a two-site dynamical coherent potential approximation for exciton-phonon interaction models corresponding to a homomorphic partition of the hamiltonian is described.
Journal ArticleDOI
Coherent Cluster Theory for Static and Dynamic Disordered Systems on Bethe Lattices
TL;DR: In this paper, a new systematic cluster theory beyond the single-site coherent potential approximation is presented for averaged one-particle Green's functions, developed in augmented space and illustrated for site-diagonal disorder.
References
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Journal ArticleDOI
The theory and properties of randomly disordered crystals and related physical systems
TL;DR: A review of the methods for determining the behavior of solids whose properties vary randomly at the microscopic level, with principal attention to systems having composition variation on a well-defined structure (random "alloys") can be found in this paper.
Journal ArticleDOI
Single-Site Approximations in the Electronic Theory of Simple Binary Alloys
TL;DR: In this paper, a single-band model Hamiltonian is used to describe the electronic structure of a three-dimensional disordered binary alloy, and several common theories based on the single-site approximation in a multiple-scattering description are compared with exact results for this Hamiltonian.
Journal ArticleDOI
A Reformulation of the Coherent Potential Approximation and Its Applications
TL;DR: In this paper, the authors give a formalism to calculate from the first principle the electronic structure of substitutionally disordered alloys in the coherent potential approximation (CPA), based on the t-matrix of the muffin-tin potential and extend the KKR method of the energy band calculation to concentrated alloys.
Journal ArticleDOI
Coherent Potential Approximation. Basic concepts and applications
Fumiko Yonezawa,Kazuo Morigaki +1 more
Journal ArticleDOI
Localized States of a Binary Alloy
TL;DR: In this article, a non-degenerate tight-binding band arising primarily from one constituent of a substitutional alloy is considered, and an approximate calculation of their spectral weight is carried out.
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