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Electron-ion Interaction: Dielectric Screening and Non-Adiabatic Dynamics in Materials

BaC6

Wednesday, May 26, 2017

High-performance computing enables quantum-mechanical studies of material properties with unprecedented accuracy: Many-body perturbation theory is now capable of predicting electronic and optical properties in excellent agreement with experiment. Real-time time-dependent density functional theory is an accurate yet efficient approach to investigate electrons interacting with fast-moving ions. In this talk I will provide insight into how these approaches can be used to study the impact of dielectric screening contributions due to free carriers and lattice polarizability on optical and excitonic properties of oxide and perovskite semiconductors. These materials have exciting optoelectronic and photovoltaic applications, which justifies that large interest in their optical properties. It will be quantified how screening due to free carriers and lattice polarizability reduces excitonic effects, tremendously changing the shape of the optical absorption spectrum and reducing exciton binding. I will also show how time-dependent density functional theory quantitatively describes non-adiabatic dynamics of electrons and ions for solid materials that are subject to particle radiation.