Events Calendar

Computational Science Distinguished Seminar Series

Speaker: Vikram Gavini, University of Michigan

Talk Title: Large-scale electronic structure calculations of extended defects in materials

Abstract: Defects play a crucial role in influencing the macroscopic properties of solids—examples include the role of dislocations in plastic deformation, dopants in semiconductor properties, and domain walls in ferroelectric properties. These defects are present in very small concentrations (few parts per million), yet, produce a significant macroscopic effect on the materials behavior through the long-ranged elastic and electrostatic fields they generate. Notably, the strength and nature of these fields, as well as other critical aspects of the defect-core are all determined by the electronic structure of the material at the quantum-mechanical length-scale. However, carefully converged electronic structure studies on extended defects, such as dislocations, have been out of reach due to the cell-size and periodicity limitations of the widely used electronic structure codes.
 
This talk will discuss the recent developments that have enabled large-scale density functional theory (DFT) calculations, paving the way for electronic structure studies of defects. The first part of the talk will discuss the development of computational methods and numerical algorithms for conducting fast and accurate large-scale DFT calculations using adaptive finite-element discretization, which form the basis for the recently released DFT-FE open-source code. The second part of the talk will focus on electronic structure studies of dislocations using the developed methods and the insights obtained into fundamental questions such as: What is the core size of a dislocation? Are forces on dislocations solely from elastic interactions? Recent studies on using DFT-FE to understand the energetics of <c+a> dislocations in Mg, and the energetics and nucleation kinetics of quasicrystals (ScZn7.33) will be discussed

Biography: Vikram Gavini is Professor of Mechanical Engineering and Materials Science & Engineering at the University of Michigan. He received his Ph.D. from California Institute of Technology in 2007. His interests are in developing methods for large-scale and quantum-accurate electronic structure calculations, numerical analysis of PDEs and scientific computing. DFT-FE, a massively parallel open-source code for large-scale real-space DFT calculations, has been developed in his group. He is the recipient of NSF CAREER Award in 2011, AFOSR Young Investigator Award in 2013, Humboldt Research Fellowship for Experienced Researchers (2012-14), USACM Gallagher Award in 2015, among others. He led the team that received the 2023 ACM Gordon Bell Prize in high performance computing.

Host: The School of Advanced Computing

More Info: https://sac.usc.edu/events/

Location: Ronald Tutor Hall of Engineering (RTH) - 526

Audiences: Everyone Is Invited

Contact: Tessa Yao

Event Link: https://sac.usc.edu/events/