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Aravind R. Asthagiri Dow Chemical Company Foundation Assistant Professor Ph.D., 2003, Carnegie Mellon University Multiscale modeling of materials Adsorption of Organic Molecules on Mineral Surfaces Modeling Novel Ferroelectric Materials Growth of nanostructured materials Email: aasthagiri@che.ufl.edu Phone: (352) 392-0868 427 CHE

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Brief Description of Current Research

Our research involves the simulation of novel materials from an atomistic level. We use a range of methods to scale the problems from highly accurate quantum mechanics descriptions that probe 10-100 atoms to more manageable simulations involving thousands of atoms based on parameterized potential models. This multi-scale modeling approach links information on the atomic level to observable macroscopic properties on experimentally relevant time and length scales. The ability to simulate the properties of materials accurately can be critical to gaining insight on the underlying phenomena, and ultimately on the design of novel materials.

Organic-molecules/mineral-surfaces interactions
Processes involving the interaction of organic material with mineral surfaces are important in biomineralization, remediation, and origin-of-life research. We are exploring the ability of chiral mineral surfaces, such as quartz and calcite, to selectively bind the different enantiomers of chiral molecules. This work may lead to the use of chiral mineral surfaces in enantioselective separation and catalysis applications.

Novel Ferroelectric materials:
Ferroelectric materials show a spontaneous polarization and can interconvert electrical and mechanical energy.  For this reason they are used in a range of applications such as tranducers and sonars. Complex solid solutions of ferroelectrics, such as Pb(Nb_2/3Mg_1/3)O₃-PbTiO₃, show very large electromechanical coupling, but are still very poorly understood.  We are using atomistic simulations to examine the effect of chemical ordering, temperature, and pressure on the electromechanical properties of these materials.

Growth of Nanostructured Materials:
There is considerable interest in nanostructures, such as nanowires and nanodots, because they have vastly different properties than those observed in bulk or on surfaces.  We are modeling the growth of metal and semiconductor nanostructures on various substrates by examining the atomic level processes that control the growth morphology.

Selected Publications

• S.R. Phillpot, S.B. Sinnott, and A. Asthagiri, “Atomic-Level Simulation of Ferroelectricity in Oxides: Current Status and Opportunities”, Annual Review of Materials Research, 37 239-270 (2007).
   
• A. Asthagiri and R.M. Hazen, “An ab inito Study of Adsorption of Alanine on the Chiral Calcite() Surface”, Molecular Simulation, 33 343-351 (2007).
   
• M. Ahart, A. Asthagiri, Z-G. Ye, P. Dera, H-K. Mao, R.E. Cohen, and R.J. Hemley, “Brillouin scattering and Molecular Dynamics study of the elastic properties of Pb(Mg₃Nb_2/3)O₃”, Physical Review B 75 144410 (2007).
   
• A. Asthagiri, Z. Wu, N. Choudhury, R. E. Cohen, “Multiscale Modeling of Relaxor Ferroelectrics”, Ferroelectrics, 333 69-78 (2006).
   
• M. Ahart, A. Asthagiri, P. Dera, H-K. Mao, R. E. Cohen, and R. J. Hemley, “Single-domain electromechanical constants for Pb(Zn_1/3Nb_2/3)O₃-4.5%PbTiO₃ from micro-Brillouin scattering”, Applied Physics Letters, 88 042908 (2006).
   
• A. Asthagiri and D.S. Sholl, “Pt thin films on the polar LaAlO₃(100) surface: A First-principles study”, Physical Review B, 73 125432 (2006).
   
• A. Asthagiri, C. Niederberger, A. Francis, L.M. Porter, P. Salvador, and D.S. Sholl, "Thin Pt Films on the Polar SrTiO₃(111) Surface: an experimental and theoretical study",  Surface Science, 537 134-152 (2003).
   
• T.D. Power, A. Asthagiri, and D.S. Sholl, "The Effect of Thermal Roughening on the Enantiospecificity of Naturally Chiral Pt Surfaces" Langmuir, 18 3737-3748 (2002).