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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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01 Jan 1994
TL;DR: In this paper, a full potential all electron method for the calculation of the electronic structure, solution of Poisson's equation, and the total energy of ordered and disordered metals and alloys is presented within the multiple scattering theory.
Abstract: Using only the angular momentum representation a full potential all electron method for the calculation of the electronic structure, solution of Poisson’s equation, and the total energy of ordered and disordered metals and alloys is presented within the multiple scattering theory. The method is applied to niobium and gives excellent agreement with other calculations and experiments.
TL;DR: In this article, a simple coherent potential approximation for the short-range order in the first coordination sphere in a binary alloy is proposed, and the residual electrical resistance is calculated in the limit of weak scattering, showing that the correlation contribution to the resistance depends very much on the position of the Fermi energy in the band.
Abstract: A simple version of the coherent-potential approximation is proposed for taking into account the short-range order in the first coordination sphere in a binary alloy. The residual electrical resistance is calculated in the limit of weak scattering. It is shown that the correlation contribution to the resistance depends very much on the position of the Fermi energy in the band, and that a nonmonotonic variation in the resistance is possible when short-range order develops in the alloy. The results are used for a qualitative interpretation of the different nature of the dependence of the resistance of alloys on the degree of short-range order.
TL;DR: In this paper, the effects of Mn concentration and thermally excited contributions (including vibrational, electronic excitation and magnetic contributions) on the phase stability of austenite and martensite from 0 K to finite temperatures in Heusler typed Ni50MnxIn50-x shape memory alloys were studied by the first-principle calculations using exact muffin-tin orbitals with coherent potential approximation (EMTO-CPA).
Abstract: The effects of Mn concentration and thermally excited contributions (including the vibrational, electronic excitation and magnetic contributions) on the phase stability of austenite and martensite from 0 K to finite temperatures in Heusler typed Ni50MnxIn50-x shape memory alloys were studied by the first-principle calculations using exact muffin-tin orbitals with coherent potential approximation (EMTO-CPA). Based on this, the martensitic transformation tendency was explored. Results show that at 0 K, the energy differences between the non-modulated (NM) martensite and the austenite become negative when extra Mn is added, indicating that the added Mn stabilizes the martensite and promotes martensitic transformation. The promoting effect increases with the increase of Mn content. At finite temperatures, the three thermal contributions (the vibrational, electronic excitation and magnetic contributions) were further calculated based on the equilibrium structure at 0 K. It was revealed that the vibrational entropies of the two phases increase with the increase of the temperature for all Mn contents. Under the two effects (temperature and Mn-content), the austenite has a larger vibrational entropy than the martensite, which indicates that the vibrational entropy contributes to promoting the martensitic transition. The Mn content and the temperature show a similar influence on the electronic entropies of the two phases. However, compared with the vibrational entropy, the contribution of the electronic entropy is much smaller. Furthermore, the influences of Mn content and temperature on the magnetic moment of both phases were simulated in their ferromagnetic state. The results show that the magnetic moments increase linearly with the Mn content, however, the influence of temperature is relatively small. Above 100 K, the magnetic moment of the austenite is higher than that of the martensite in ferromagnetic Ni50Mn29.25In20.75 alloy, suggesting that the magnetic entropy makes a similar contribution to promote the martensitic transformation, like the vibrational and electronic excitation entropies.
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TL;DR: In this article, the authors studied the nature of the electronic states in the intermediate band formed by interstitial titanium in silicon and obtained an extended metallic state with a strongly depleted density of states at the Fermi level.
Abstract: We study the nature of the electronic states in the intermediate band formed by interstitial titanium in silicon. Our single-site description combines effects of electronic correlations, captured by dynamical mean-field theory, and disorder, modeled using the coherent potential approximation and the typical medium mean-field theory. For all studied concentrations an extended metallic state with a strongly depleted density of states at the Fermi level is obtained. The self-energy is characteristic to Fermi-liquids and for certain temperatures reveals the existence of coherent quasi-particles.
15 Jun 1997-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: The thermodynamics of the one-dimensional spin 1/2 isotropic XY model with Dzyaloshinskii-Moriya interaction in random Lorentzian transverse field has been obtained exactly as discussed by the authors.
Abstract: The thermodynamics of the one-dimensional spin 1/2 isotropic XY model with Dzyaloshinskii-Moriya interaction in random Lorentzian transverse field has been obtained exactly. Using the derived exact single-particle density of states, the validity of coherent potential approximation has been examined.