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In this work, the conducting properties of graphene lattice with a particular concentration of defect (5% and 10%) has been studied. The real space block recursion method introduced by Haydock et al. has been used in presence of the random distribution of defects in graphene. This Green function based method is found to be more powerful than the usual reciprocal based methods which need artificial periodicity. Different resonant states appear because of the presence of topological and local defects are studied within the framework of Green function. [ABSTRACT FROM AUTHOR]

We use cluster generalization of the coherent potential approximation in the tight-binding linear muffin-tin orbital method to account for the effect of the local environment on electronic and magnetic properties of substitutional random alloys. This theory combines the augmented space formalism and conventional tight-binding linear muffin-tin orbital methods. In particular, we shall apply the technique to the bcc-based NiAl and fcc-based CuAu alloys and also compare with other approaches. [ABSTRACT FROM AUTHOR]

We present a systematic first-principle study of the structures, energetics and electronic structure of (ZnO)n clusters in the size range 1 ≤ n≤ 12. We show that the planar ring structures are stable for n < 8, while spheroidal structures made out of rings of (ZnO)3 and (ZnO)2 are stable for n ≥ 8. We examine the binding energies and HOMO–LUMO gaps of the clusters and try to understand our results from simple physical ideas. [ABSTRACT FROM AUTHOR]

We present here an optimized and parallelized version of the augmented space recursion code for the calculation of the electronic and magnetic properties of bulk disordered alloys, surfaces and interfaces, either flat, corrugated or rough, and random networks. Applications have been made to bulk disordered alloys to benchmark our code. [ABSTRACT FROM AUTHOR]

In this communication we shall focus on the three microscopic processes whose interplay determine the surface morphology of MBE growth: namely, surface diffusion, desorption and accretion and Schwoebel back diffusion. We gain insight into the dynamics of growth via one-loop perturbative techniques. This allows us to analyze our numerical data. We conclude that there is a crossover behavior from a roughening regime to a very long-time, large length scale smoothening regime. [ABSTRACT FROM AUTHOR]

We present calculations of the electronic and magnetic structure of thin films of Ni, using the recursion technique based on the tight-binding linearized muffin-tin orbitals basis. We find that the surface layers of free standing Ni thin films do carry enhanced magnetic moment. [ABSTRACT FROM AUTHOR]

We have studied the electronic properties like density of states and band structures and also the ground state properties like formation energy, cohesive energy, bulk modulus and structural energy of NiPt system using the linearized muffin-tin orbital method introduced by Andersen.[sup 1,2] In an earlier communication we had argued that both charge neutrality and scalar relativistic corrections are very important for the high concentration of Pt alloys. The calculations here, were, therefore, carried out with charge neutrality as well as with and without scalar relativistic correction for comparison. [ABSTRACT FROM AUTHOR]

The equilibrium structures and cohesive energies of small Cu[SUBn] clusters using the full-potential muffin-tin orbitals (FP-LMTO) based molecular dynamics (MD) have been studied for n ≤ 9. The results obtained have been compared with other chemical methods. We propose the FP-LMTO-MD technique to be a useful starting point of more empirical methods which can efficiently deals with larger cluster sizes relevant for nanoparticles. [ABSTRACT FROM AUTHOR]

We determine the lowest energy structures of small (11-20 atoms) copper clusters. The semi-empirica1 Equivalent Crysta1 Theory (ECT) is used in conjunction with the Metropolis Monte Carlo algorithm to determine the equilibrium geometry of each cluster via simulated annealing. The optimum structures of the clusters in this size range are found to be derived from icosahedra1 structures. The 13-atom cluster is an icosahedron and the 19-atom is a double-icosahedron. The other sizes show structures related to these. The 11-atom clusters, however, show somewhat different structures. We propose the ECT as an efficient tool for developing starting structures for more chemically accurate, first principles and therefore computationally very demanding, approaches. [ABSTRACT FROM AUTHOR]

The formalism developed earlier for the study of optical properties of random semiconducting alloys has been applied to the ternary alloy GaAs[SUBx]Sb[SUB1-x]. The effects of randomness in the optical transition matrix element has been shown within the formalism. [ABSTRACT FROM AUTHOR]

A formalism has been developed for the study of optical properties of random semiconducting alloys. The effects of randomness and clustering in the optical transition matrix element may be incorporated within our formalism. [ABSTRACT FROM AUTHOR]

We had earlier presented a computationally feasible and fast technique for obtaining the electronic structure of random alloys which allowed us to incorporate short-ranged order and effects like clustering and local lattice distortions due to size mismatch effects. The technique combined the augmented space recursion with the tight-binding LMTO. We have recast the formalism in a way that allows us to sample many more configurations states and bring the basic equations in a one-to-one correspondence with the screed KKR formalism. [ABSTRACT FROM AUTHOR]