Landau levels in disordered alloys

The electronic structure of a substitutionally disordered alloy in a uniform magnetic field has been studied on a simple model of scattering potentials (zero range potentials). The coherent potential and single-site aproximation have been employed. It turned out that in wide energy region the Dingle temperature, characterizing the decay of the amplitude of de Haas — van Alphen oscillations, is determined by the part of self-energy which does not depend on magnetic field. The field dependent part is important only for a few Landau levels at the bottom of the band. The results can be applied to simple metals and semi-metals.     

Effect of short-range order on electronic and magnetic properties of disordered Co-based alloys

We here study electronic structure and magnetic properties of disordered CoPd and CoPt alloys using augmented space recursion technique coupled with the tight-binding linearized muffin tin orbital (TB-LMTO) method. Effect of short-range ordering present in disordered phase of alloys on electronic and magnetic properties has been discussed. We present results for magnetic moments, Curie temperatures and electronic band energies with varying degrees of short-range order for different concentrations of Co and try to understand and compare the magnetic properties and ordering phenomena in these systems.     

Electronic structure of disordered BCC alloys

This paper describes and analyses a self-consistent cluster coherent potential approximation calculation of the electron density of states of a random, binary alloy on abcc lattice.     

Self-consistent cluster theory of disordered alloys

The coherent potential approximation is not sufficiently accurate to describe the details of the energy spectrum of a disordered alloy when the mean free path is short. A new approximation based on treating, self-consistently, clusters of sites is introduced.     

同步辐射技术在无序合金结构与性能研究中的应用

同步辐射装置作为大科学装置和多学科的实验平台,已成为物质结构,特别是无序物质结构研究最有效、最先进的手段之一.文章简单介绍了同步辐射技术在研究无序合金结构、液态合金结构、非晶多形态相变以及块体金属玻璃力学行为等方面的应用.随着第三代的上海同步辐射光源(SSRF)的建立,国内用户利用先进的同步辐射技术开展研究又多一个选择,相信上海光源对中国科研的发展将起剑积极的推动作用.     

Pair effects in disordered ternary alloys

A generalization of the coherent potential approximation and its diagrammatic equivalent have been used to include pair effects in the electronic self-energy of compositionally disordered-model ternary alloys.     

同步辐射技术在无序合金结构与性能研究中的应用

同步辐射装置作为大科学装置和多学科的实验平台,已成为物质结构,特别是无序物质结构研究最有效、最先进的手段之一.文章简单介绍了同步辐射技术在研究无序合金结构、液态合金结构、非晶多形态相变以及块体金属玻璃力学行为等方面的应用.随着第三代的上海同步辐射光源（SSRF）的建立,国内用户利用先进的同步辐射技术开展研究又多一个选择, 相信上海光源对中国科研的发展将起到积极的推动作用.     

Magnetooptical absorption in binary disordered alloys

The coherent potential approximation is used to compute the antisymmetric part (which depends linearly on the spin-orbital interaction) of the optical conductivity tensor of a disordered ferromagnetic alloy. The scattering of magnetized conduction electrons on the impurity potential of the alloy and on thermal vibrations of the lattice is considered.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 95–99, September, 1976.In conclusion we would like to express our deep gratitude to E. I. Kondorskii for posing the problem and for a number of valuable comments during discussions of the results.     

Upper critical field of disordered NbNi alloys

The critical fields for disordered Nb-Ni alloys are measured in the concentration region from 40 to 60 at% Nb down to temperatures below 0.1T_c. For these alloys T_c varies by a factor of 8 while the density of states, calculated from the slope of the critical field close to T_c, is about 1 (eV atom)⁻¹ independent of concentration. The critical fields are enhanced over the maximum value consistent with the Werthamer-Helfand-Hohenberg theory. It is suggested that weak localization effects contribute to the enhanced critical field of Nb₄₀Ni₆₀.     

First-principles investigations on thermodynamic properties of the ordered and disordered Si0.5Ge0.5 alloys

The structure, formation energy, and thermodynamic properties of Si_0.5Ge_0.5 alloys are investigated through first-principles method. The ordered and disordered structures of Si_0.5Ge_0.5 compounds are considered. Our results show that thermodynamic instabilities of Si_0.5Ge_0.5 alloys at 0 K can be judged from the calculated formation energy. However, the alloy might be prepared at specified environment owing to the entropy effects considered. Moreover, the temperature dependence of the heat capacity, Debye temperature and thermal expansion coefficient of ordered and disordered structures are discussed.     

Remarks on strongly correlated disordered cpa alloys

Strongly correlated disordered metallic alloys are discussed, within Roth's linerization method. We show that the inclusion of the complete Roth's band shift introduce a correlation-induced off-diagonal disorder, which may be treated within the extended CPA approach.     

Local distribution approach to disordered binary alloys

We study the electronic structure of the binary alloy and (quantum) percolation model. Our study is based on a self-consistent scheme for the distribution of local Green functions. We obtain detailed results for the density of states, from which the phase diagram of the binary alloy model is constructed, and discuss the existence of a quantum percolation threshold.     

Equilibrium vacancy concentration in disordered binary alloys

The equilibrium vacancy concentration in disordered binary alloy is calculated in this paper. The calculations are performed in the configuration approximation, explicitly taking into account various types of vacant site neighborhoods. The self-diffusion coefficient is determined as a function of alloy composition.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 79–83, May, 1972.     

Effective field theory for disordered magnetic alloys

Disordered alloys of magnetic atoms of two types have been considered within the Ising model based on the calculation and analysis of the distribution function of effective fields acting on magnetic atoms. The Curie temperatures, magnetizations of two magnetic “sublattices,” threshold concentrations of magnetic atoms, and magnetic phase diagrams of alloys have been calculated.