Berlin 2015 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 81: Electronic Structure Theory: Many-Body Effects (organized by O)

TT 81.5: Poster

Mittwoch, 18. März 2015, 18:15–21:00, Poster A

Atomistic Modeling of Optical Coefficients in Layered Materials — •Christian Vorwerk, Caterina Cocchi, and Claudia Draxl — Humboldt Universität zu Berlin and IRIS Adlershof, 10099 Berlin, Germany

The optical properties of a material are fully determined by the complex dielectric tensor. Comparison with measured data however, requires accounting for the experimental setup. This is in particular important for molecular materials, owing to their anisotropic nature.

We apply a 4x4-matrix formalism [1] to calculate optical coefficients of layered anisotropic materials, combining ab initio calculations of the dielectric tensor with the solution of Maxwell’s equations. This approach [2] allows us to investigate the impact of polarization and incidence angle of the incoming light beam on the spectra of layered materials, having a specific orientation with respect to the substrate. We apply the formalism to optical as well as to X-ray absorption spectra, computing the full dielectric tensor with the all-electron full-potential code exciting [3] by means of many-body perturbation theory. Our prototypical target systems are different polymorphs of sexithiophene, crystals of functionalized pentacenes, self-assembled monolayers of azo-benzenes, and more.

[1] P. Yeh, Surf. Sci. 96, 41 (1980). [2] P. Puschnig and C. Ambrosch-Draxl, Adv. Eng. Mater. 8, 1151 (2006). [3] A. Gulans et al., J. Phys.: Condens. Matter 26, 363202 (2014).