panchapakesan ganesh 
materials theory and computation
 

Research and Development Staff Scientist

Center for Nanophase Materials Sciences

Oak Ridge National Laboratory

Tel: 1-865-574-1999

Fax:1-865-574-1999

Email: ganeshp AT ornl.gov

  1. 1.Develop atomistic models and fundamental understanding of Li/Na-ion batteries.


We use a wide range of methods, from quantum monte-carlo to electronic density functional theory to classical reactive- and non-reactive force-field modeling to simulate and understand the structure, dynamics and reactions in Li- and Na-ion battery materials, in a wide range of length- and time-scales. The current focus is in understanding electrolytes and their interfaces with electrodes as well as in employing a combination of theoretical methods to understand conversion electrodes (e.g. Na/Li-{Sn,Sb}), pseudocapacitors (e.g. LixNb2O5) and solid-electrolytes (e.g. Li3PS4) with the aim of optimizing energy and power density with minimum capacity loss for thousands of cycles.




  1. 2.Establish an understanding of graphene-based solid-fluid interphases for supercapacitance and catalysis applications.


We use a range of methods from ab initio molecular dynamics to reactive force field simulations to understand the interactions of fluids (such as water) with epitaxial graphene and carbon nanostructures.  The current focus is in understanding and quantifying key control parameters (defects, epitaxial-strain, functionalization etc.) which determine interfacial atomic structure and charge-transfer, on experimentally verified structural models that we build.




  1. 3.Establish an absolute understanding of fluid-mediated catalysis on oxide supported nanoparticles


We use electronic density functional theory based methods to understand the role of water in mediating technologically important reactions on oxide (TiO2, ZrO2 etc.) supported gold nanoparticles.  The previous focus was in understanding and quantifying the role of surface hydroxyls on reaction pathways and kinetics. Currently the role of interfacial water in direct mediation of technologically important surface reactions is being investigated with high level theory and global optimization methods.




  1. 4.Investigation of self assembly and other emergent behavior in superconducting organic salts on metal support


Origin of strong electronic correlations and resulting superconductivity in 3-dimensional organic superconductors (e.g. ET- and BEDT-salts) opens the possibility of their controlled growth and characterization on solid surfaces with characteristic electronic properties (metals, insulators, topological insulators etc.). Understanding the emergent correlated electron physics at the nanoscale at solid-molecule interfaces should allow us to engineer superconducting materials bottom-up.  We employ a range of high-level electronic structure methods to investigate this in conjunction with experiments and other theory experts in strongly correlated methods at CNMS.



    

  1. 5.Understand and predict new and improved multiferroic oxide materials, both in bulk, heterostructure and thin-film geometries,  for various electronic and energy harvesting applications


We employ a combination of high level electronic structure theory, effective Hamiltonian methods and genetic algorithm based structure prediction techniques to predict bulk, heterostructure and thin-film properties of multiferroic oxide materials. We work closely with experimentalists at ORNL to synthesize and characterize them, to build a coherent  understanding of the origin of their novel properties.




  1. 6.Obtain a thorough understanding of Fe-based superconductors


Using a combination of high level density functional theory methods, cluster-expansion based defect thermodynamics, Wannier function methods and lattice Hubbard model techniques, in collaboration with other theorists at ORNL, we try to understand the nature of superconductivity in pure and impure Fe-based superconductors in bulk and thin-film geometries.




  1. 7.High throughput structure search using genetic algorithms for layered materials


We are interested in discovering new layered materials using structure search methods and characterizing their properties using computations. Focus is on identifying polytipsm and/or polymorphism at the nanoscale in layered materials.










© Copyright, P. Ganesh, ORNL, Sunday, February 9, 2014