EXAFS Studies of Zn1-xMnxS Ternary Compounds

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Liquid Nitrogen and Room Temperature Reflectivity Spectra of Cd1−x\text{}_{1-x}Fex\text{}_{x}Se in the 0.5-6.0 eV Energy Range

The reflectivity measurements for mixed crystals Cd$\text{}_{1-x}$Fe$\text{}_{x}$Se (0.00 ≤ x ≤ 0.10) have been carried out in an energy range of 0.5-6.0 eV at 300 and 77 K. The influence of Fe$\text{}^{2+}$(3d$\text{}^{6}$) states on the changes in the energy positions of the reflectivity maxima E$\text{}_{0}$, E$\text{}_{1}$(A$\text{}_{1}$), E$\text{}_{1}$(A$\text{}_{2}$), and E$\text{}_{1}$(B) is analyzed and the obtained results are consistent with the models existing in the literature

Local structure of ternary semiconducting random solid solutions: EXAFS of Cd1-xMnxTe

The nearest-neighbor distances around Te atoms in the random semiconducting alloy Cd1-xMnxTe have been determined by the extended x-ray-absorption fine-structure technique. The distribution of the anion-cation distances is bimodal. A model of the microscopic structure of the zinc-blende-type A1-xBxC ternary alloys based on a random distribution of cations has been developed. The model describes the bimodal distribution of nearest-neighbor distances in terms of distortion of the anion sublattice, using only the lattice constant of the alloy and the bond-stretching constants of each binary component. Within the framework of this model we consider also the problem of the structural stability of Cd1-xMnxTe

Reflectivity Spectra of Cd1−x\text{}_{1-x}Mnx\text{}_{x}F2\text{}_{2} in the 5-35 eV Energy Range

The reflectivity spectra of Cd$\text{}_{1-x}$Mn$\text{}_{x}$F$\text{}_{2}$ crystals, in the 5-35 eV energy range at 300 and 77 K, were investigated. The observed changes in the shape of spectra, caused by increase of the Mn content, are compared with the calculated band structure of pure CdF$\text{}_{2}$ and with the already available results of XPS experiments for these crystals. The increasing concentration of Mn results in the blurring of the reflectivity structures and shifts the energy of direct exciton (as compared to pure CdF$\text{}_{2}$). Qualitative arguments (hybridization of Mn$\text{}^{2+}$ 3d and F$\text{}^{-}$ 2p states) can describe these effects but a quantitative explanation would require a detailed band structure calculation for these compounds

Site Occupation Preferences in CdMnTeSe Quaternary Alloys. EXAFS Data Analysis

Site occupation preferences in zinc-blende Cd1-xMnxTe1-ySey (0≤x≤0.15; 0.0≤y≤0.20) quaternary alloys have been determined by the Extended X-ray Absorption Fine Structure (EXAFS) analysis. The experimental data have been collected with the use of synchrotron radiation for Se- and Mn-K edges. For both K edges, the preferences of manganese distribution around selenium have been observed and analyzed. The Mn-Se with Cd-Se, and Mn-Se with Mn-Te distances have been found as linearly dependent on concentration of Se and Mn. The average coordination numbers of Mn around Se versus Mn composition was approximated by the quadratic behavior instead of the linear dependence expected for the virtual crystal approximation, in which a full random distribution of elements in the sublattices is assumed. The obtained results support the preferential occurring of Mn and Se ions in the considered compounds. A structural and magnetic interaction reasons of the preferences were discussed

Manganese Distribution in CdMnTeSe Crystals. EXAFS Data Analysis

The extended X-ray absorption fine structure (EXAFS) technique has been used to investigate the first shell coordination in zinc-blende quaternary Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te$\text{}_{1-y}$Se$\text{}_{y}$ (0.0 ≤ x ≤ 0.15; 0.0 ≤ y ≤ 0.20) alloys. The experimental data have been collected with the use of synchrotron radiation. All the nearest-neighbour distances have been found as linearly dependent on Se and Mn concentration. For each composition a consistent deviation from full random distribution of Mn atoms around Se and Te atoms was observed. Possible reasons of preferential Mn-Se over Mn-Te pairing were discussed

D-CORE TRANSITIONS IN ZNTE, CDTE AND HGTE

We have measured the reflectivity spectra of monocrystalline ZnTe, CdTe and HgTe between 5 and 35 eV. We have interpreted the sharp structures above approximately 10 eV as transitions originating in the metal uppermost d levels. The structures give a picture of the projected densities of states of the conduction bands and supply a better understanding of their states. © 1986 Società Italiana di Fisica

Local structure of ternary semiconducting random solid solutions: Extended x-ray-absorption fine structure of Cd1-xMnxTe

The nearest-neighbor distances around Te atoms in the random semiconducting alloy Cd1-xMnxTe have been determined by the extended x-ray-absorption fine-structure technique. The distribution of the anion-cation distances is bimodal. A model of the microscopic structure of the zinc-blende-type A1-xBxC ternary alloys based on a random distribution of cations has been developed. The model describes the bimodal distribution of nearest-neighbor distances in terms of distortion of the anion sublattice, using only the lattice constant of the alloy and the bond-stretching constants of each binary component. Within the framework of this model we consider also the problem of the structural stability of Cd1-xMnxTe.</p

Model of the local structure of random ternary alloys:Experiment versus theory

We have performed an extended x-ray-absorption fine-structure (EXAFS) measurement of Cd1-xMnxTe solid solutions for various concentrations x in the single-phase range 0≤x≤0.7. Data have been collected on the Mn K, Cd LIII, and Te LIII edges. We have found well-defined different nearest-neighbor Cd-Te and Mn-Te distances almost independent of x. A model of the microscopic structure of the zinc-blende-type A1-xBxC ternary alloys based on a random distribution of cations has been developed. The model describes the bimodal distribution of near-neighbor distances in terms of distortion of the anion sublattice (the cation sublattice is assumed to remain fixed) with use only of the lattice constants of the alloy and the bond-stretching constants of each binary component. Its application to Cd1-xMnxTe and In1-xGaxAs alloys is proved to be in good agreement with the EXAFS results. Within the framework of this model we also consider the problem of the structural stability of Cd1-xMnxTe