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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, a virtual crystal approximation (VCA) based on density functional theory (DFT) with generalized gradient approximation (GGA) was used to calculate the ferromagnetic variation of transition metal monoboride.
Abstract: Calculations of magnetism are made on transition metal monoboride of Fe ( 1 - x ) Co x B , with the scale 0 ⩽ x ⩽ 1 . In this paper, we calculate the ferromagnetic variation of transition metal monoboride by the method of virtual crystal approximation (VCA), based on density-functional theory (DFT) with generalized gradient approximation (GGA). The variations of ferromagnetism of Fe ( 1 - x ) Co x B alloys by the first-principle spin-polarized calculations are in agreement with experimental results, the prediction of the Stoner model and the Korringa–Kohn–Rostoker (KKR) method with coherent potential approximation (CPA). The spontaneous magnetization decreases with increasing x and vanishes at around x = 0.85 . This complies with earlier findings. The instability at around x = 0.8 is elucidated by electron filling of the Fe 3d orbital both from valence and interstitial electrons.
11 citations
TL;DR: In this article, the first-principles calculations were applied to shed light on the magnetic properties of the host compound CdTe co-doped with the vanadium and the phosphorus elements.
11 citations
TL;DR: In this article, the origin of ferromagnetism in dilute magnetic semiconductors is discussed based on ab initio calculations for Mn-doped GaN, GaP, GaAs and GaSb.
Abstract: We discuss the origin of ferromagnetism in dilute magnetic semiconductors based on ab initio calculations for Mn-doped GaN, GaP, GaAs and GaSb. We use the Korringa-Kohn- Rostoker method in connection with the coherent potential approximation to describe the substitutional and moment disorder. Curie temperatures (T C) are calculated from first-principles by using a mapping on a Heisenberg model in a mean field approximation. It is found that if impurity bands are formed in the gap, as it is the case for (Ga, Mn)N, double exchange dominates leading to a characteristic √c dependence of T C as a function of the Mn concentration c. On the other hand, if the d-states are localized, as in (Ga, Mn)Sb, Zener’s p-d exchange prevails resulting in a linear c-dependence of T C. In order to have more precise estimations of T C, effective exchange coupling constants J ij’s are calculated by using the formula of Liechtenstein et al. It is found that the range of the exchange interaction in (Ga, Mn)N is very short. On the other hand, in (Ga, Mn)As the interaction is weaker but long ranged. Monte Carlo simulations show that the T C values of (Ga, Mn)N are very low since percolation is difficult to achieve for small concentrations and the mean field approximation strongly overestimates T C. Even in (Ga, Mn)As the percolation effect is still important.
11 citations
TL;DR: In this article, the formation energy and resistivity for domain walls in permalloy (fcc-Ni 8 5 Fe 1 5 ) were determined using the fully relativistic spin-polarized screened Korringa-Kohn-Rostoker method for layered systems.
Abstract: To determine the formation energy and resistivity for domain walls in permalloy (fcc-Ni 8 5 Fe 1 5 ) we use the fully relativistic spin-polarized screened Korringa-Kohn-Rostoker method for layered systems and the corresponding Kubo-Greenwood equation in the context of the (inhomogeneous) coherent potential approximation. We find that the difference in formation energy between 90° and 180° domains becomes very small if the domain wall width increases. Furthermore, we show that regardless of the configuration within a domain wall the in-plane components of the resistivity are larger than in a single domain and, in particular, that the anisotropic magnetoresistance ratio within the domain wall vanishes.
11 citations
TL;DR: In this article, the generalized coated coherent potential approximation method was used to derive the mathematical formulae for the extended effective medium theory to investigate the optical properties of disordered media composed of core-shell cylinders with the core layer consisting of epsilon-less-than-one material.
11 citations