Indian Institute of Technology I I T Campus

Powai, Mumbai 400 076 Powai, Mumbai 400 076

Education: I.Sc., University of Bihar, India (1976); B.Sc., University of Bihar, India (1979)

M.Sc., Indian Institute of Technology, Kanpur, India (1981); Ph. D., University of North Carolina, Chapel Hill, USA (1989)

Awards: National Merit Scholarship (1976-78, 1979-81); UNC Board of Governors’ Fellowship (1985-85)

Areas of Research Interest: Theoretical study of electronic structure of ordered and disordered alloys, clusters and nanoparticles; study of phase stability and ab initio calculations of alloy phase diagrams, magnetic properties of bulk and surfaces of solids; ab initio calculations of electronic structure using molecular dynamics simulations and order-N method.

Assistant Professor (1994-2003), Associate Professor (2003-2007), Professor (2007- ~) Indian Institute of Technology Bombay, Mumbai, India

At IIT, I have set up a computing laboratory, albeit small, dedicated entirely to electronic structure calculations. In order to bring the computing laboratory at par with similar facilities abroad, at least in terms of physics, I have done the following:

Using density-functional methods, studied electronic structure and electron-phonon interaction in compressed Yttrium.
Applied fixed-spin moment method to study incipient magnetism in MgCNi₃ and its alloys.
Studied electronic structure of transition-metal wires of Fe, Co and Ni in Carbon nanotubes.
Using ab initio methods, some of which I have developed, calculated the electronic structure of the newly discovered superconductor MgB₂ and its alloys. The calculations explain the variation in Tc in MgB₂upon substitution with various elements.
Based on ab initio results, predicted possible superconductivity in hole-doped LiBC and Graphite.
Implemented the code for spin-polarized charge self-consistent Korringa-Kohn-Rostoker coherent-potential approximation in the atomic-sphere approximation (KKR-ASA CPA) for calculating the electronic structure of substitutionally disordered alloys on complex lattices. The code uses an efficient approach to solve the CPA equations, includes the generalized gradient approximation for exchange-correlation potential, and a robust program for k-space integration. The code is being used to study the magnetic properties of the alloys of newly discovered superconductor MgCNi₃, and other transition metal binary alloys.
Developed the formalism for robust k-space integration for calculating the Green’s functions of ordered and disordered alloys.
Implemented the code for spin-polarized charge self-consistent Green’s function-linear muffin-tin-orbital (LMTO) method for calculating the electronic structure of dilute alloys on complex lattices. The code is being used to study the role of host d-band in local moment formation when a magnetic impurity is dissolved in a metal with d-band.
Adapted a set of full-potential codes (~10,000 lines) based on the (i) linear muffin-tin orbital method, (ii) linear augmented plane wave method, and (iii) pseudopotential method for calculating the energetics of ordered alloys obtainable within the local-spin-density or generalized-gradient approximation.
Developed a real-space-based method for calculating the electronic structure of atomic clusters.
Worked on a BRNS sponsored project (Rs. 5.42 lacs) to study the phase stability of SYNROC constituents.
Working on implementing an order-N approach, developed by Faulkner et al. and Abrikosov et al., for calculating the electronic structure of systems with arbitrary distributions of atoms in real space using our KKR-ASA CPA code.
Working with ab initio molecular dynamics simulations program to study tetrahedrally-bonded a-C and other carbon nanostructures. Also, working on incorporating spin polarization in the molecular dynamics simulation code.

Since joining the institute I have taught various courses at B. Tech. and M. Sc. levels. In particular, I have taught Mechanics (PH 101) to the first year B. Tech. students for four years, Quantum Mechanics (PH 422), Electromagnetic theory (PH 424), Introduction to Condensed Matter Physics (PH 429), Condensed Matter Physics (PH 522) and Advanced Simulation Techniques in Physics to B. Tech. and M. Sc. Students. I have guided two Ph. D. students, and currently two more Ph. D. students are working under me. In addition, I have also guided several B. Tech and M. Sc. project students.

Postdoctoral Work, Lawrence Livermore National Laboratory, Livermore, USA, 1991-1994

Developed the formalism for calculating effective-cluster interactions in the atomic-sphere approximation (ASA), as primary input to ab initio phase diagram calculations of substitutional alloys. Developed the theory for calculating the nonspherical charge densities of random alloys. Successfully applied my theory to the study of phase stability of random alloys to Ni-Pt, Al-Li, and Cu-Zn systems.

Postdoctoral Work, University of California, Berkeley, USA, 1989-1991

Developed a theory of random alloys in the atomic-sphere approximation that is much more flexible and efficient than previous theories, and allows a direct comparison with the electronic structure of ordered alloys calculated with the linear muffin-tin orbital method.

Graduate Work in Physics, University of North Carolina, Chapel Hill, USA, 1983-1989

During my graduate study I made an extensive study of the electronic behaviour in crystalline solids, an impurity in a cluster, surfaces, interfaces, and microclusters. In order to achieve this I did the following as a dissertation project:

Developed the formalism for charge self-consistent electronic structure calculations using the recursion method.
Implemented the k-space Green’s function method within the linear muffin-tin orbital method for studying the electronic structure of dilute alloys.
Performed a complete calculation of impurity resistivity and thermoelectric power for 3d-transition metals embedded in bulk aluminum and copper by Green’s function-LMTO and recursion methods.

Indian Institute of Technology, Kanpur, India, 1979-1983

Following completion of the M. Sc. Degree, in an independent research project I studied the order parameter approach to the theory of liquid metals with M. Youssouff. For the M. Sc. research project I did experiments on the vapor deposition of thin films of a-Si:H and a-Ge.

Computing Experience

Based on my theoretical developments, I have written and tested a set of computer codes (~9000 lines) for carrying out spin polarized self-consistent-field Korringa-Kohn-Rostoker coherent-potential approximation (SCF-KKR-CPA) calculations in the ASA for random alloys on complex lattices. Also wrote and tested computer programs for carrying out charge-self-consistent solution of the Dyson equation for dilute impurities, using Green’s function-LMTO (~5000 lines) and the recursion methods (~4000 lines).

I have managed the computer network within the department from 1995 to 2000, and provided operational assistance to the departmental computing facility. I was In-charge of the departmental computing facility from July 1999 to July 2001.

Computer Systems: Cray, mini supercomputers, IBM mainframes, and workstations.

Environments: Solaris, OSF, Unix, Linux, MS-DOS, Windows; Languages: Fortran 90, C, Macsyma, and Mathematica.

Publications

Number of Publications: 47 papers (Journals: 37; Conference proceedings: 10).