arXiv subjects

Atisdipankar Chakrabarti

Publications and source records attributed to Atisdipankar Chakrabarti.

5 recordsLinked to original sources

arXiv2007

Electronic, magnetic and optical properties of random Fe-Cr alloys

In this communication we have studied the electronic structure, magnetic and optical properties of bcc \fecr alloys in the ferromagnetic phase. We have used the augmented space recursion technique coupled with tight-binding linearized muffin-tin orbital technique (TB-LMTO-ASR) as well as the coherent-potential approximation based on the Korringa-Kohn-Rostocker method (KKR-CPA). Also the plane wave projector augmented wave (PAW) method has been used with the disorder simulated by the special quasi-random structure method f or configuration averaging (SQS). This was to provide a comparison between the different methods in common use for random alloys. Moreover, using the self-consistent potential parameters from TB-LMTO-ASR ca lculations we obtained the spin resolved optical conductivity using the generalized recursion technique proposed by Müller and Vishwanathan.

cond-mat.dis-nn↗

arXiv2006

Effect of short-range order on the electronic structure and optical properties of the CuZn alloy : an augmented space approach

In this work we have combined the generalized augmented space method introduced by one of us with the recursion method of Haydock et al (GASR), within the framework of the local density functional based linear muffin-tin orbitals basis (TB-LMTO). Using this we have studied the effect of short-range ordering and clustering on the density of states, optical conductivity and reflectivity of 50-50 CuZn alloys. Our results are in good agreement with alternative techniques. We argue that the TB-LMTO-GASR is a feasible, efficient and quantitatively accurate computational technique for the study of environmental effects in disordered binary alloys.

cond-mat.dis-nn↗

arXiv2006

Study of the one dimensional Holstein model using the augmented space approach

A new formalism using the ideas of the augmented space recursion (introduced by one of us) has been proposed to study the ground state properties of ordered and disordered one-dimensional Holstein model. For ordered case our method works equally well in all parametric regime and matches with the existing exact diagonalization and DMRG results. On the other hand the quenched substitutionally disordered model works in low and intermediate regime of electron phonon coupling. Effect of phononic and substitutional disorder are treated on equal footing.

cond-mat.dis-nn↗

arXiv2006

Effect of Short-ranged Order on the electronic structure and optical properties of the CuZn alloy : an augmented space approach

We report here a study of the effect of short-ranged ordering on the electronic structure and optical properties of CuZn alloys. We shall use the augmented space recursion technique developed by us in conjunction with the tight-binding linear muffin tin orbitals basis.

cond-mat.dis-nn↗

arXiv2001

Augmented space recursion for partially disordered systems

Off-stoichiometric alloys exhibit partial disorder, in the sense that only some of the sublattices of the stoichiometric ordered alloy become disordered. This paper puts forward a generalization of the augmented space recursion (ASR) (introduced earlier by one of us (Mookerjee et al 1997(*))) for systems with many atoms per unit cell. In order to justify the convergence properties of ASR we have studied the convergence of various moments of local density of states and other physical quantities like Fermi energy and band energy. We have also looked at the convergence of the magnetic moment of Ni, which is very sensitive to numerical approximations towards the k-space value 0.6 $μ_{B}$ with the number of recursion steps prior to termination.

cond-mat↗