With recent advances in computer hardware and development of new numerical methods, computation has joined experiment and theory as one of the three main branches of science. The essential part in a computation is not the use of computers, but the systematic application of numerical techniques in place of, and/or in addition to, analytical methods to study and discover many unexpected physical phenomena that would have been otherwise intractable. Using state of the art theoretical techniques such as first principle density functional method (for which Walter Kohn got the Nobel Prize in 1998), I plan to study properties of materials of reduced size and dimension particularly at the nanoscale regime. These include clusters, their interaction with surfaces, multilayers and thin films. My research will not only be aimed at providing an in-depth understanding of the evolution of properties from atoms to bulk, but also in guiding the future experiments for making materials with uncommon electronic, magnetic and optical properties.
In addition to serving as a bridge between atoms and the bulk, nanoscale systems offer attractive possibilities for technological applications. In last few years application of fundamental discoveries in nanoscale systems has helped developing multi-billion dollar industries. Examples include giant magnetoresistance multilayers for computer memories, superlattice confinement effect for lasers and optoelectronic devices, the discovery of new catalysts for automobile industry and the synthesis of nanocomposites for drug delivery in the pharmaceutical field. A synopsis of some of my research plans is given below.
1. Transition metals and their oxides and nitrides
Transition metals and their oxides, nitrides represent an important class of materials as they play major roles in high temperature superconductivity, catalysis and corrosion. Recently experiments have been directed to an understanding of the stability, magnetic and optical properties of these clusters. I plan to study electronic, magnetic and catalytic properties of transition metal and their oxide clusters. It is hoped that this study will give insight into the origin of discrepancies between various experiments and will add valuable information for developing single domain magnetic devices and new catalytic materials.
The semiconductor industry is already expecting serious breakdown of further miniaturization of electronics devices in next few years since quantum effects interfere with the operation of sub-micron transistors. It is suggested that this problem could be avoided by exploring electron spin devices where one exploits the spin of the electron that has been so far neglected in electronic devices. Experiments on such direction have just begun and magnetic clusters on semiconductor surfaces offer an appealing route. However, an understanding of cluster-surface interactions involves many challenging phenomena, which can be facilitated by using various theoretical schemes mentioned here.
3. Molecular Electronics
One of the phenomenon which is drastically modified due to small size is conductivity. The conductivity of nanoscale materials is dominated by surface effects which is in turn very sensitive to the exact numbers of atoms or molecules present in the system, the type of interface inhomogeneity which are practically absent in the bulk material. This suggests that one can "tune" the conductivity of these materials at the atomic level. But before this becomes reality in semiconductor industry one needs to have understanding of many underlying physical principles. I plan to explore the conductivity of single molecules to atomic wires both free standing systems as well as when are deposited on suitable surfaces or encapsulated in matrices using quantum mechanical calculations. Other ideal possible matrix for isolating magnetic clusters is carbon nanotube. A close collaboration between the theory and experiment is expected.
4. Study of molecules relevant to biological problems: Photosynthetic Water Oxidation
The first family of manganese-oxo complexes containing the cubane-shaped Mn4O4 core has been isolated recently. These complexes hold promise as potential models of the inorganic core of the photosynthetic water oxidation enzyme that produces O2 on a global scale. The structure of the inorganic core of the enzyme and the mechanism by which it catalyzes water oxidation/oxygen production is an intensely debated topic. My research will be focused to account for the unusual electronic properties and reactivities of these molecules using computational electronic structure methods. This is just an example of the application of state of the art theoretical study to the problems having biological importance. This is an emerging field and many interesting related phenomena could be studied at a microscopic level using quantum mechanical calculation.
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Department of Physics, Applied Physics, and Astronomy Room SC 3C06
Troy, New York 12180-3590 USA
Telephone: (518) 276-3673
Last Modified: 27 Sep, 2005 by Puneet Khetarpal