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

Current Projects: Understand and Discover New Topological Quantum Materials for Quantum Information Science Applications I lead an integrated theory and experimental effort to understand the role of defects in inducing topological phase-transitions into exotic phases such as (magnetic) Weyl-phase, quantum-anomalous hall phase etc., in bulk and interfacial quantum-materials. The goal of the effort is to understand ways of realizing a topological superconductor, where Majorana fermions can be realized, at as high an operating temperature as possible. Develop an Integrated Approach To Discover by Design Fast Ionic Conducting Solids We are building a framework to integrate high-throughput computations and analysis with material synthesis and a range of experimental characterization techniques such as neutron scattering, electron microscopy and transport measurements to discover by design novel ionic conducting solids for proton and lithium-ion conduction for applications in fuel-cell and battery devices. High-throughput computations are performed via workflows written in Fireworks and analysis is performed using Pymatgen. Develop Atomistic Models and Fundamental Understanding of Li/Na-ion Battery Electrolytes and Electrodes 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}), anodes (Li/carbon-nanostructures), 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. Fluid-Mediated Catalysis on Oxide Based Nanoparticles We use electronic density functional theory based methods to understand the role of water in mediating technologically important reactions on oxides (TiO2, ZrO2, NiO etc.) and oxide 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. Emergent Behavior due to Defects at Oxide Heterostructure Interfaces We perform high performance computations to understand the emergent electronic and incipient ionic properties at perfect, defective and nano-structured oxide interfaces. The goal is to understand how defects and nano-structuring can be used to either tune or reveal new properties at oxide heterostructure interfaces. High-Throughput Discovery of New Layered Ferroic Materials We are using high performance computing and thermodynamic and kinetic modeling to discover new layered (multi) ferroic materials in close collaboration with experimentalists who perform novel synthesis and surface/bulk characterization measurements. The goal is to discover new multi-ferroic materials in layered geometries that can also be potentially integrated with each other (i.e. multi-layer heterostructures) or with other solids for new device concepts. Interface Directed Self Assembly and Emergent Behavior in Supported Charge-Transfer Molecular Salts 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. Selected Past Projects: 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. 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.

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© Copyright, P. Ganesh, ORNL, Wednesday, August 28, 2019