The effect of impurities on quantum chemical parameters of single-walled nanotubes (SWNTs) was studied using density functional theory (DFT). The density of states (DOS), Fermi energy and thermodynamic energies of (5,5) carbon nanotubes were calculated in the presence of nitrogen impurity. It was found that this nanotube remains metallic after being doped with one nitrogen atom. The partial den...

CeAl2 has attracted considerable attention because of its unusual properties including a proposed competition between Kondo compensation and anti-ferromagnetic spin-density wave ordering observed at low temperatures. Here we present results of a self-consistent spin-polarized LMTO band study of CeA^. In its paramagnetic state the Ce-f band is about 1 eV wide and, although principally above Ej.,...

We investigated a series of nickel-based oxyarsenides LnNiAsO (Ln=La, Ce, Pr, Nd, Sm) compounds. CeNiAsO undergoes two successive anti-ferromagnetic transitions at TN1=9.3 K and TN2=7.3 K; SmNiAsO becomes an anti-ferromagnet below TN≃3.5 K; NdNiAsO keeps paramagnetic down to 2 K but orders anti-ferromagnetically below TN≃1.3 K. Superconductivity was observed only in Kramers non-magnetic LaNiAsO...

The theoretical study of magnetic semiconductors using the dynamical coherent potential approximation (dynamical CPA) is briefly reviewed. First, we give the results for ferromagnetic semiconductors (FMSs) such as EuO and EuS by applying the dynamical CPA to the s-f model. Next, applying the dynamical CPA to a simple model for A1−xMnxB-type diluted magnetic semiconductors (DMSs), we show the re...

In this work, we study the t-J model using a two-pole approximation within composite operator method. We choose basis of two operators -- constrained electrons and their spin-fluctuation dressing approximate currents in order to compute corresponding Green's functions. exploit algebraic constraints obeyed by close set self-consistent equations that is numerically solved. This allows determine p...

The recent discovery of 2D magnetic materials, which are compounds transition metals (TM) with other elements, has opened new avenues for basic research on low-dimensional magnetism and potential applications in spintronics. To further explore magnets pure TM is an interesting topic. Based the first-principles calculations, here a strategy obtaining monolayer magnets, i.e., depositing atoms gra...

In this work, we study the t-J model using a two-pole approximation within composite operator method. We choose basis of two operators -- constrained electrons and their spin-fluctuation dressing approximate currents in order to compute corresponding Green's functions. exploit algebraic constraints obeyed by close set self-consistent equations that is numerically solved. This allows determine p...