MEMS Seminar: Partition of Unity Finite Element Method for Quantum Mechanical Materials Calculations

Feb 8

Wednesday, February 8, 2017

1:30 pm - 2:30 pm
Fitzpatrick Center Schiciano Auditorium Side A


Professor N. Sukumar

The current state-of-the-art for large-scale quantum-mechanical simulations is the planewave (PW) pseudopotential method, as implemented in codes such as VASP, ABINIT, and many others. However, since the PW method uses a global Fourier basis, with strictly uniform resolution at all points in space, it suffers from substantial inefficiencies in calculations involving atoms with localized states, such as first-row and transition-metal atoms, and requires significant nonlocal communications that compromises parallel efficiency. Real-space methods such as finite-differences and finite-elements have partially addressed both resolution and parallel-communications problems, but have been plagued by one key disadvantage relative to PW: excessive number of degrees of freedom (basis functions) needed to achieve the required 1 mHa (chemical) accuracy in total energy. In this talk, I will present a real-space partition of unity finite element (PUFE) approach to solve the Kohn-Sham equations (coupled Schrodinger and Poisson equations) of density functional theory. In the PUFE method, we build the known atomic physics into the solution process to solve the Schrodinger eigenproblem using partition-of-unity enrichment techniques in finite element analysis. The method developed herein is completely general, applicable to any crystal symmetry and to both metals and insulators alike. Total energy calculations for full self-consistent Kohn-Sham calculations will be presented for LiH that has

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Siler, Katherine