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Coherent potential approximation

About: Coherent potential approximation is a research topic. Over the lifetime, 1930 publications have been published within this topic receiving 36805 citations.


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TL;DR: In this article, first principle atomistic simulations of quantum transport in Si nanochannels under uniaxial tensile strain are presented. But the authors employ a semi-local exchange along with coherent potential approximation to investigate the transport properties of two-terminal Si nanodevices composed of large number of atoms and atomic dopants.
Abstract: We report parameter-free first principle atomistic simulations of quantum transport in Si nanochannels under uniaxial strain. Our model is based on the density functional theory (DFT) analysis within the Keldysh nonequilibrium Green's function (NEGF) formalism. By employing a recently proposed semi-local exchange along with the coherent potential approximation we investigate the transport properties of two-terminal Si nanodevices composed of large number of atoms and atomic dopants. Simulations of the two-terminal device based on the NEGF-DFT are compared quantitatively with the traditional continuum model to establish an important accuracy benchmark. For bulk Si crystals, we calculated the effects of uniaxial strain on band edges and effective masses. For two-terminal Si nanochannels with their channel length of ~ 10 nm, we study the effects of uniaxial strain on the electron transport. With 0.5% uniaxial tensile strain, the conductance along [110] direction is increased by ~ 8% and that along [001] is increased by ~ 2%, which are comparable with the other reported results. This paper qualitatively and quantitatively shows the current capability of first principle atomistic simulations of nanoscale semiconductor devices.

11 citations

Journal ArticleDOI
TL;DR: In this paper, a discussion of the Rudermann-Kittel interaction in binary alloys for a wide range of compositions is given, and the coherent potential approximation is used as it is ideally suited to the Green function formalism of the earlier work.
Abstract: A discussion is given of the Rudermann-Kittel interaction in binary alloys for a wide range of compositions. The authors extend earlier work (1969) in which was discussed the effect of spin-independent scattering of electrons on the indirect exchange. The coherent potential approximation is used as it is ideally suited to the Green function formalism of the earlier work. The important new feature appearing is an exponentially decaying factor that will cause a more rapid falloff in the range of the interactions than the normally assumed R-3 form.

10 citations

Journal ArticleDOI
TL;DR: In this article, the wave vector resolved electronic density of states (WDE) of a 1 T−TiSe2 crystal containing Frenkel defects was calculated using a tight binding formalism, and an extra peak in the ΓA direction at 1.5 eV was traced back to a resonance caused by titanium vacancies.
Abstract: Using a tight binding formalism the wave vector resolved electronic density of states has been calculated in the coherent potential approximation for an 1 T−TiSe2 crystal containing Frenkel defects. Additional structure originating from disorder is discussed. An extra peak in the ΓA direction at 1.5 eV binding energy can be traced back to a resonance caused by titanium vacancies.

10 citations

Journal ArticleDOI
TL;DR: In this paper, the relationship between the interchain and intrachain interactions was analyzed for an isolated chain and a trigonal crystal by the tight-binding approximation, and the behavior of the interaction parameters obtained from their calculations indicated that the chain-like nature of a trigonic crystal becomes less distinguished as the increase of x.
Abstract: To study the relation between the interchain and intrachain interactions as well as to compare the chain-like features with the bulk characteristics in chalcogenide alloys, the Te concentration ( x ) dependence of the optical gap E g is theoretically analyzed for Se 1- x Te x of an isolated chain and a trigonal crystal. In the first place, band structures are calculated for an isolated chain and for a trigonal crystal by the tight-binding approximation. The behaviour of the interaction parameters obtained from our calculations indicates that the chain-like nature of a trigonal crystal becomes less distinguished as the increase of x . Secondly, the electronic density of states of Se 1- x Te x is calculated by the coherent potential approximation. The results show that the optical gap E g for a bulk mixture decreases as x increases while E g for a chain does not change very much for x ≥0.2. These results are in good agreement with the experimental data.

10 citations

Journal ArticleDOI
TL;DR: In this paper, the authors present physical reasons for the coherent potential approximation (CPA) calculation method's abillity to predict little band gap bowing or alloy scattering, while at the same time predicting large deviation from virtual crystal behavior in other energy ranges.
Abstract: Physical reasons are presented for the coherent potential approximation (CPA) calculation method’s abillity to predict little band gap bowing or alloy scattering, while at the same time predicting large deviation from virtual crystal behavior in other energy ranges. Accurate treatment of structural properties requires that calculations be doubly self‐consistent: a density functional method plus CPA is needed. Experimental values of bond energies are greater than those predicted by simple theories. Weakened HgTe bonds in alloys help to explain the loss of Hg when the materials undergo surface treatments.

10 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20234
202222
202127
202030
201930
201840