Regensburg 2013 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 88: Focus Session: Frontiers of electronic structure theory VII (O, jointly with HL, TT)

HL 88.7: Vortrag

Donnerstag, 14. März 2013, 17:30–17:45, H36

Real-structure effects from ab-initio calculations — •Andre Schleife — Condensed Matter and Materials Division, Lawrence Livermore National Laboratory, Livermore, CA, USA

By harnessing the power of supercomputers, computational materials science is becoming a field that enables insight into fundamental materials physics. It is inevitable to further push ab-initio approaches, allowing them to account for effects that are important at the forefront of experimental research.

I will present the solution of the Bethe-Salpeter equation as a recent theoretical-spectroscopy technique and how it is extended and used to understand real-structure effects in oxide and nitride semiconductors. This talk will illustrate the success of our modification of this framework to describe the interplay of free electrons and excitonic effects in n-doped ZnO. Combining a cluster expansion scheme and electronic-structure calculations allows to explore the potential for band-gap tailoring in oxide and nitride alloys. These material systems are a driving force of current semiconductor technology, e.g. for solar cells and solid-state lighting; understanding fundamental effects will help to overcome performance limits.

In addition, computational materials science can replace dangerous experiments, e.g. in the context of radiation damage: I will present large-scale simulations of non-adiabatic electron-ion dynamics based on real-time time-dependent density functional theory that explain electronic stopping as an important mechanism responsible for radiation damage when fast H or He ions penetrate aluminum.