Related papers: Disorder effects in electronic structure of substi…
We study a simplified model of the electronic structure of compounds of the type of La$_{1-x}$Sr$_x$MnO$_3$. The model represents each Mn$^{4+}$ ion by a spin S=1/2, on which an electron can be added to produce Mn$^{3+}$. We include two…
We examined the characteristics of a metal-insulator transition on a two-dimensional non-bipartite lattice when both disorders and electron interactions are present. Using a real-space renormalization group method and finite-size scaling…
These lectures provide an introduction to the theory of disordered interacting electron systems. In particular, we concentrate on those aspects which are fundamental for the problem of the metal-insulator transition due to the interplay of…
In the manganites $RE_{1-x}AE_{x}$MnO$_{3}$ ($RE$ and $AE$ being rare-earth and alkaline-earth elements, respectively) the random distribution of $RE^{3+}$ and $AE^{2+}$ induces random, but correlated, shifts of site energies of charge…
We perform a theoretical study, using {\it ab initio} total energy density-functional calculations, of the effects of disorder on the $Mn-Mn$ exchange interactions for $Ga_{1-x}Mn_xAs$ diluted semiconductors. For a 128 atoms supercell, we…
We present calculated electron excitation spectra for the LaMO_3 series (M=Cr-Ni) obtained within ab-initio band structure calculations for the real geometric and magnetic structures. The calculated results show good agreement with the…
The local atomic disorder and the electronic structure in the environment of manganese atoms in LaMnO_3 has been studied by x-ray absorption spectroscopy, over a temperature range (300K to 870K) covering the orbital ordering transition…
Interfacial charge transfer in oxide heterostructures gives rise to a rich variety of electronic and magnetic phenomena. Designing heterostructures where one of the thin-film components exhibits a metal-insulator transition opens a…
We investigate the interplay of the electronic and structural transition in La$_{0.2}$Sr$_{0.8}$MnO$_{3}$. The transport and specific heat measurements exhibit unusual evolutions and signature of a first order phase transition around 265 K.…
We use a model previously formulated based on the double exchange mechanism and diagonal disorder to calculate magnetization and conductivity for La_{1-x}Sr_xMnO_3 type crystals as a function of temperature. The model represents each…
Cation disorder is an important design criterion for technologically relevant transition-metal (TM) oxides, such as radiation-tolerant ceramics and Li-ion battery electrodes. In this letter, we use a combination of first-principles…
Density functional theory (DFT) calculations are used to study the magnetic and ferroelectric properties of Sr$_{1-x}$Ba$_{x}$MnO$_3$, with focus on $x=0.5$, under isotropic volume expansion/compression and biaxial strain. Our results…
Experimental results on the metal-insulator transitions and the anomalous properties of strongly interacting two-dimensional electron systems are reviewed and critically analyzed. Special attention is given to recent results for the…
The physics of manganites appears to be dominated by phase competition among ferromagnetic metallic and charge-ordered antiferromagnetic insulating states. Previous investigations (Burgy {\it et al.}, Phys. Rev. Lett. {\bf 87}, 277202…
We have carried out an investigation of the structural, magnetic, transport and superconducting properties of Fe$_{1+z}$Te$_{1-x-y}$Se$_x$S$_y$ ceramic compounds, for $z=0$ and some specific Se (0$\leq$ x $\leq$ 0.5) and S (0 $\leq$ y…
The electronic structure and magnetic properties of La_{1-x}A_{x}MnO_3 are investigated. It is assumed that, at the outermost layer, the environment of the Mn ions does not have cubic symmetry. The e_g orbitals are split and the double…
We present a theory of the metal-insulator transition in a disordered two-dimensional electron gas. A quantum critical point, separating the metallic phase which is stabilized by electronic interactions, from the insulating phase where…
In recent years, disorder has been shown to be crucial for the understanding of diluted magnetic semiconductors. Effects of disorder in these materials are reviewed with the emphasis on theoretical works. The types and spatial distribution…
The spectral properties of a disordered electronic system at the metal-insulator transition point are investigated numerically. A recently derived relation between the anomalous diffusion exponent $\eta$ and the spectral compressibility…
In order to manipulate the properties of graphene, its very important to understand the electronic structure in presence of disorder. We investigate, within a tight-binding description, the effects of disorder in the on-site (diagonal…