Regensburg 2013 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 60: Graphene - Theory (jointly with DS, HL, MA, and O)
TT 60.1: Vortrag
Donnerstag, 14. März 2013, 15:00–15:15, H17
Influence of non-local exchange-correlation and spin-orbit interaction on electronic and optical properties of graphene, silicene, germanene, and tinene — •Lars Matthes1, Olivia Pulci2, Paola Gori3, and Friedhelm Bechstedt1 — 1Institut für Festkörpertheorie und -optik, Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, 07743 Jena — 2Dipartimento di Fisica, Università di Roma "Tor Vergata", via della Ricerca Scientifica 1, 00133 Rome, Italy — 3CNR-ISM, Via Fosso del Cavaliere 100, 00133 Rome, Italy
We present first-principles studies of the optical absorbance of the group-IV honeycomb crystals graphene, silicene, germanene, and tinene. We account for many-body effects on the optical properties by using the non-local hybrid functional HSE06. The optical absorption peaks are blue-shifted due to quasi-particle corrections, while the influence on the low-frequency absorbance remains unchanged and reduces to the universal value πα,1,2 where α is the Sommerfeld fine-structure constant. However, in silicene, germanene and tinene an electronic band gap arises at the Dirac-point due to spin-orbit splitting and parabolic bands with a very small effective mass emerge. Consequently, the low-frequency absorbance is modified due to the spin-orbit induced fundamental absorption edge. We demonstrate numerically that the absorbance increases at the fundamental absorption edge.
[1] A. Geim et al., Science 320, 1308 (2008)
[2] F. Bechstedt, L. Matthes et al., Appl. Phys. Lett. 100, 261906 (2012)