Hello, A yearly allocation for the LCRC cluster has been requested with the following updated information: Submitter/PI: Milind Malshe Project Name: MD_Potential_Oxide Division: CSE Project title: Synthesis Science of Functional Layered Complex Oxides Associated funding: Strategic Initiative on Materials for Energy (LDRD-2012-188-R1) Other Systems: NERSC: ~ 400000 core-hours Science: The principal objective of this project is development of new, more flexible and more accurate many-body potentials for the description of interatomic interactions in various inhomogeneous systems and use of these potentials in large scale molecular dynamics (MD) and Monte Carlo (MC) simulations of the synthesis and properties of new functional materials such, e.g., as layered complex oxides. The results of the proposed studies will aid the ongoing collaborative experimental effort at MSD, APS, CNM and CSE in defining synthesis schedules and conditions – types of elements, temperature, pressure, etc. - that will result in materials with the desired properties and functionalities. We will also explore the properties of new materials as a function of the chemical identity and number/thickness of layers, strain, and nature and concentration of defects, including the mechanisms of formation of defects (e.g., as induced by temperature or pressure). Project description: Initial efforts are devoted on exploring the structural and dynamical/thermal properties of surfaces and thin films of complex layered oxides using empirical potentials. We focused on the study of strontium titanate (STO) as a paradigm. This choice was motivated by the synthesis and characterization work on this system currently underway within our experimental component. Surface relaxations in a thin film of STO are analyzed and the role of epitaxial strain arising due to mismatch between the lattice constants of the film and substrate material is being investigated. Large-scale MD runs are being performed using the parallelized version of the DL_POLY and LAMMPS packages. The high scalability of these packages with the system size is well documented. The number of atoms in our planned simulations will vary from a few tens of thousands to hundreds of thousands and possibly a few millions. These MD runs will be complemented by the state-of-the art densit y functional theory (DFT) calculations on these systems. The planned DFT computations will be carried out with the VASP and Quantum Espresso packages. Both the packages exhibit high parallelization scalability for the electronic structure computations needed for this project. Concurrently, we are also pursuing the development of new, robust, flexible, and more accurate potentials for mimicking the interatomic interactions in layered complex oxide materials. The effort will be pursued in two directions. The first aims at incorporation of variable charges and polarizabilities into the existing potentials, thereby generalizing their applicability for simulating defects in oxide materials which are known to play an important role in governing materials properties. The second is a principally new approach based on the neural networks (NN) methodology and evolutionary (specifically, genetic algorithms (GA)) techniques. A particularly attractive aspect of the NN approach is that no a priori assumption about the functional form of the potential is made, which results in a much higher degree of flexibility and robustness. The codes NN and GA based potentials will be developed and implemented in MATLAB. An additional algorithmic advantage of the NN and GA m ethodologies is that they are inherently amenable to high degree of parallelization. Work on this aspect and the related methodological developments will be an important part of the planned activities. The number of project members is 4. Project URL: http://blogs.anl.gov/major_initiatives/materials-for-energy/ Current FY Hours Used: undetermined amount New FY Requested allocation: 480000 Q1: 120000 Q2: 120000 Q3: 120000 Q4: 120000 Justification: The allocation request is based on MD test runs of 2 ns for a thin film of SrTiO3 consisting of 20,000 atoms performed with the DL_POLY package on Carver at NERSC: Cores Wall time (s) 8 38880 16 31629 32 24843 64 16282 128 8698 256 3895 (A better parallelization scaling is achieved for this system, as evaluated over runs of 2 ns in duration, with a larger number of cores.) Thank You, The LCRC Accounts System