Brown University School of Engineering

Engineering Seminar: Joint Materials/Solid Mechanics

Thursday, April 25, 2019

4:00pm - 5:00pm

School of Engineering

Barus and Holley, 166

Professor Vikram Gavini, Dept of Mechanical Engineering and Dept of Materials Science and Engineering at the University of Michigan, will present a talk: “Large-Scale Real-Space Electronic Structure Calculations.”
Abstract: Electronic structure calculations, especially those using density functional theory (DFT), have been very useful in understanding and predicting a wide range of materials properties. Despite this success of DFT, and the tremendous progress in theory and numerical methods over the decades, the following challenges remain. Firstly, the state-of-the-art implementations of DFT suffer from cell-size and geometry limitations, with the widely used codes in solid state physics being limited to periodic geometries and simulation domains containing at most a few thousand atoms. This limits the complexity of materials systems that are accessible to DFT calculations. Secondly, most electronic structure calculations rely on the pseudopotential approximation, treating only the valence electrons. Recent studies have elucidated many scenarios where the pseudopotential approximation and the widely used pseudopotentials are unsatisfactory. Lastly, there are many materials systems (such as strongly-correlated systems) where the widely used model exchange-correlation functionals are inaccurate. Addressing these challenges will enable large-scale all-electron quantum-accuracy DFT calculations, and will significantly advance our predictive modeling capabilities of complex materials systems. 
This presentation will discuss our recent advances towards addressing the aforementioned challenges. In particular, the development of computational methods and numerical algorithms for large-scale real-space reduced-order scaling DFT calculations using adaptive finite-element discretization will be presented, which form the basis for the recently released DFT-FE open-source code. The computational efficiency, scalability and capability of DFT-FE will be presented, and contrasted with other widely used codes. In an effort to overcome the limitation of the pseudopotential approximation, recent progress in developing accurate, efficient, and scalable all-electron DFT calculations will be presented. Further, recent efforts, and related thoughts, towards developing a framework for a data-driven approach to improve the exchange-correlation description in DFT will be discussed. 
This is joint work with Phani Motamarri, Sambit Dias and Bikash Kanungo.