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.

Electronic Structure of Mixed Valence State

Abstract: A model for the mixed valence state is presented. The basic lattice is composed of N trivalent rare earth ions. Extra N electrons enter either the localized f level at each ion site or the conduction band. When an electron occupies the f level of rare earth ion, this ion becomes divalent ion. The electron can jump from the f level to the conduction band and vice versa through the hybridization between these states. The effect of the strong intra-atomic Coulomb and the exchange interactions between the f electrons on the hybridized states is studied by applying the coherent potential approximation. The gap in the density of states and/or the mobility gap appear around the f level, and the Fermi level is located within the gap. The energy of the paramagnetic state is shown to be lower than that of the ferromagnetic state.

Transverse Ising model with substitutional disorder: an effective-medium theory

Abstract: An effective-medium theory is presented for the substitutionally disordered transverse Ising model above its transition. The equations of motion for the relevant Green functions are decoupled in RPA. The disorder then occurs through a local parameter and can be treated in the spirit of the single-site coherent potential approximation. Fully self-consistent results are computed at the transition for the transition temperature, densities of states and spectral function. Simple features of the results can be understood using a generalized virtual-crystal approximation which accounts for damping due to disorder. Extensions of the theory to include intrinsic damping, more than one spin per unit cell and coupling to phonons are discussed.

The theory of disordered alloys. I. Continued fractions and off-diagonal disorder

Abstract: A continued fraction technique is used to derive an approximation to the density of states of a disordered alloy with a tree of Bethe lattice. The approximation in the case of only diagonal disorder provides a new simple derivation of the coherent potential approximation for a certain density of states. For an alloy with both diagonal and off-diagonal disorder the density of states is given in terms of the solution of a certain cubic equation. The self energy in this case is also obtained and used to provide the starting point for a theory of alloys with both diagonal and off-diagonal disorder and a general lattice which is equivalent to a special case of the theory of Blackman et al. Extensive calculations are presented.

Random Kondo alloys investigated with the coherent potential approximation

Abstract: The interplay between the Kondo effect and disorder is studied. This is done by applying a matrix coherent potential approximation and treating the Kondo interaction on a mean-field level. The resulting equations are shown to agree with those derived by the dynamical mean-field theory. By applying the formalism to a Bethe tree structure with infinite coordination, the effects of diagonal and off-diagonal disorder are studied. Special attention is paid to the behavior of the Kondo and the Fermi-liquid temperature as function of disorder and concentration of the Kondo ions. The nonmonotonous dependence of these quantities is discussed.

Complex inorganic solids : structural, stability, and magnetic properties of alloys

Abstract: Precipitation of Disordered Ni-X Solid Solution Phases in Off-stoichiometric Ordered Ni3X Alloys -An Atomic Scale Study of the Physical Properties of Delta Plutonium and Pu:Al Alloys -Ab Initio Thermodynamics and Structural Studies of Cationic Disordered MgAl2O4 Spinel -Computer Simulation of Molten and Glassy Silica and its Mixtures with Sodium Oxide and Aluminum Oxide -A Computer Model of Carbonitride Precipitation in Steel -Current and Future Applications of CALPHAD Technology -Phase Stability and Ordering in (Ga,Mn)As Alloys -Vacancy Ordering and Non-stoichiometry in TiC1-xox and TiN1-xox -Vacancy-Mediated Phase Transformations: Homogeneous or Heterogeneous? -Calculation of the Phase Diagrams of Alloys with Non Pair Atomic Interactions within the Ring Approximation -Modelling of Phase Separation in Iron-based Ternary Alloys -Short-range Order Parameters in fcc Binary Alloys -Dependence of Ordering Process in Ni-based 1 1/2 0 Alloy on Alloying Elements -Changes of LRO in Anisotropic L l0-Ordered FePd -Ordering Processes Analyzed by Phase Field Method, CVM and PPM -Phase Distribution and Transformation Dynamics Using in-situ Synchrotron Diffraction Methods -Monte Carlo Study of the Precipitation Kinetics of Al3Zr in Al-Zr -Examination of Multi-component Diffusion Between Two Ni-Base Superalloys -Curvature and Basis Function Effects on Electronic and Transport Properties of Carbon Nanotubes -The Behavior of Solid Solutions in Geological Transport Processes: The Quantization of Rock Compositions by Fluid-Rock Interaction -Ab-Initio Study of Diluted Magnetic Semiconductors Variation of Elastic Shear Constants in Transition Metal Alloys -Theoretical Strength, Magnetism and Stability of Metals and Itermetallics -Rejuvenation of Deformation-Damaged Material by Magnetic Annealing - A New Approach to Grain BoundaryEngineering -Coherent-Potential Approximation within the Exact Muffin-tin Theory -Charge Distributions in Metallic Alloys: A Charge Excess Functional Theory Approach -Local Charge Distributions in Metallic Alloys: A Local Field Coherent Potential Approximation Method -On the Development of Alloy Theory -Microscopial Derivation of Ginzburg-Landau-type Functionals for Alloys and their Application to Studies of Antiphase and Interphase Boundaries -Investigation of Structures and Properties of C3P4 Alloy using First-principles Electronic Structure Calculation