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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 paper, the cyclotron resonance absorption spectrum in a Wigner crystal is calculated by considering Coulomb interaction between the excitations at different sites and averaging over different realizations of the spin arrangement within the coherent potential approximation.
Abstract: The cyclotron resonance absorption spectrum in a Wigner crystal is calculated. Due to band-structure effects, the electrons at different sites have different cyclotron resonance frequencies depending on their spin orientation. To calculate the absorption line shape we consider effects of Coulomb (dipole-dipole) interaction between the excitations at different sites. The averaging over different realizations of the spin arrangement is done within the coherent potential approximation. The results show a crossover from a double-peak spectrum at small filling factors where the dipole-dipole interaction is weak, to a single-peak spectrum at filling factors larger than about 1/6 where the interaction effects are completely dominating. As the electron filling factor is increased further, the absorption line becomes broader due to radiation damping. The results are in good agreement with experiments.
17 Dec 2012
TL;DR: In this paper, the authors compared virtual crystal approximation (VCA) and dynamical coherent potential approximation (dynamical CPA) to study the conduction electron states and ferromagnetism of electron-doped EuO theoretically.
Abstract: To study the conduction electron states and ferromagnetism of electron-doped EuO theoretically, we have applied two approximations to the s-f model and compared their results: virtual crystal approximation (VCA) and dynamical coherent potential approximation (dynamical CPA). The results of both approximations explain the anomalous magnetization curve experimentally observed in Gd-doped EuO and/or Eu-rich EuO with a low electron density, while only the result of dynamical CPA can explain the electron-density dependence of the Curie temperature TC. The TC calculated by VCA shows the monotonous increase with electron density, while the TC calculated by dynamical CPA shows a maximum for a certain electron density. The mechanism of TC increase is also discussed.
01 Jan 1998
TL;DR: In this paper, the phase stability and magnetism in Ni-Pt alloys were studied using first-principles method, and it was shown that the interstitial electrons are instrumental in reducing the local magnetic moment of Ni in oredered Ni3Pt.
Abstract: Using first-principles method, we study phase stability and magnetism in Ni-Pt system. We find that (i) inclusion of relativistic effects is essential for an accurate description of the phase stability and the magnetism in Ni-Pt alloys and (ii) the interstitial electrons are instrumental in reducing the local magnetic moment of Ni in oredered Ni3Pt, in agreement with experiments. This requires going beyond the so-called atomic-sphere approximation through the inclusion of corrections terms for overlap effects.
TL;DR: In this article, a coherent potential approach for disordered Heisenberg spin systems and alloys by the coherent energy approach was rigorously developed to involve cluster effects and off-diagonal randomness, and an approximating method based on the exact formulation was presented for linear chains in magnetic systems.
Abstract: A formulation for disordered Heisenberg spin systems and alloys by the coherent potential approach is rigorously developed to involve cluster effects and off-diagonal randomness. In the momentum representation the diagonal matrix elements of the averaged t-matrix are obtained in a Fourier-analysed form. Equations to determine the unknown Fourier coefficients of the coherent energy are given exactly by requiring that each Fourier coefficient of the t-matrix vanish. An approximating method based on the exact formulation is presented for linear chains in magnetic systems. This applies to general short-range potentials and always retain the translational symmetry.