1. Phase Stability of Alloys: The main research activity of my group is in the electronic structure calculations of alloys, ordered or substitutionally disordered, using density functional formalism. The density functional approach allows the study of the ground state properties such as equilibrium lattice constant, cohesive energy, bulk modulus, electronic specific heat, densities of states, magnetic moment (both spin and orbital contribution), and other electronic properties of solids. The electronic structure calculations of ordered alloys are carried out using the full-potential linear muffin-tin orbital method or the pseudopotential method.

         The electronic structure of susbstitutionally disordered alloys is based on the determination of a uniform medium to represent the substitutional alloy using the coherent potential approximation in the so-called Korring-Kohn-Rostoker atomic-sphere approximation mode. Within this framework perturbation-like methods are used to determine concentration-dependent effective cluster interactions and through them ordering energies and stable structures. Currently, we are studying the magnetic properties of MgB₂-3d Transition-Metal, MgCNi₃-Co, and other alloys.

2. Electronic Structure of Superconducting MgB₂ and other Related Materials: The recent discovery of superconductivity in MgB₂ at 39 K has necessitated a better understanding of its electronic structure in the normal as well as the superconducting state. Using the ab initio techniques, some of which we have developed, we are studying the electronic structure and the electron-phonon coupling of MgB₂, other diborides and related materials. Such an approach is expected to be useful in finding alloys with improved superconducting properties.

3. Order-N Method: Recently, Faulkner et al. and Abrikosov et al. have formulated an order-N approach for calculating the electronic structure of systems with arbitrary distributions of atoms in real space. The method allows an efficient calculation of the onsite and the intersite Green’s function of the atoms in the system, thereby making possible the study of metallic alloys with varying degree of order. We plan to implement this approach in our KKR-ASA CPA code, and apply it to study short-range order effects and core-level chemical shifts in alloys.

4. Molecular Dynamics Simulations: The Car-Parrinello method provides an efficient approach for analyzing the motion of atoms, which enables us to study the equilibrium as well as the non-equilibrium properties of systems such as surfaces, interfaces, clusters, and bulk materials. I plan to apply the molecular dynamics simulations to study (a) the effects of short-range order in metallic systems such as Cu-Pd and Ni-V, (b) electronic structure of defects in semiconductors, (c) the sp² and sp³ mixing in carbon systems.

Most of the computational methods that I use to describe the electronic structure of metallic alloys can be easily adapted to semi conducting solids. Similarly, my experience in the study of metallic clusters can be very helpful in understanding many interesting phenomena exhibited by mesoscopic systems such as quantum wires and quantum dots. The work on semi conducting solids has great potential for bringing in funding, domestic as well as foreign. I hope to continue the study of semi conducting materials and mesoscopic systems in close cooperation with Prof. D. S. Misra.