The electronic structure of oxygen in silicon as revealed by volume visualization of Ab Initio calculations

Abstract

We apply volumetric rendering to the interpretation of atomic-scale data generated from quantum molecular dynamics computations. In particular, we examine silicon computations, and we discover that volumetric visualization of the computed 3D electronic charge density is a valuable tool for identifying defect states in silicon lattices in which oxygen atoms occur as impurities. Rendering of several judiciously selected ranges of charge density in translucent colors provides an effective means of identifying broken or altered molecular bonds and induced charge excesses in the lattice. The resulting 3D images reveal important features missed previously in 2D charge density contour maps. We find that stereoscopic "blink comparison" of image pairs is an extremely valuable way to study the structural differences among various configurations and that time animation provides significant insight into the molecular dynamics. We conclude that our success with silicon implies that the technique has the potential to provide a significant benefit to other problems in computational condensed matter physics.