Berlin 2015 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 100: ZnO and its relatives
HL 100.1: Vortrag
Freitag, 20. März 2015, 09:30–09:45, EW 203
First-principles Evidence for Intermediate Hole Polarons in ZnO — •Honghui Shang1, Christian Carbogno1, Patrick Rinke1,2, Matthias Scheffler1, Hikmet Sezen3, Fabian Bebensee3, Chengwu Yang3, Maria Buchholz3, Alexei Nefedov3, Stefan Heissler3, and Christof Woell3 — 1Fritz-Haber-Institut der MPG, Berlin, DE — 2Aalto University, Helsinki, Fi — 3Karlsruhe Institute of Technology, Karlsruhe, DE
We performed density functional theory calculations at the hybrid-functional level (HSE06) to investigate the nature of the polaronic states in ZnO. Our calculations confirm that neither small (i.e., strong coupling) electron nor hole polarons are stable in ZnO, in agreement with previous studies [1]. The binding energy of large polarons (i.e., weak coupling) was determined by evaluating the renormalization of the band edges due to the zero-point motion of the atoms [2]. However, for intermediate polarons at intermediate coupling strength, the harmonic approximation breaks down, and there is currently no first-principle theory. We use the HSE06 effective masses to calculate the Fröhlich coupling constants α. Feynman’s path integral technique then yields an intermediate hole polaron, whose binding energy of 245 meV and associated peaks in the optical absorption spectrum are consistent with infrared reflection absorption spectroscopy. [1] J. B. Varley et al., Phys. Rev. B 85, 081109(R)(2012), [2] G. Antonius et al., Phys. Rev. Lett. 112, 215501 (2014)