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O: Fachverband Oberflächenphysik

O 35: Poster Session I (Metal, semiconductor and oxide substrates: structure and adsorbates; Graphene)

O 35.75: Poster

Dienstag, 12. März 2013, 18:15–21:45, Poster B1

Excitonic oscillator strength of metallic and semiconducting carbon nanotubes — •Eike Verdenhalven and Ermin Malic — Institut für Theoretische Physik, Nichtlineare Optik und Quantenelektronik, Technische Universität Berlin, Germany

The intrinsic oscillator strength of single-walled carbon nanotubes (CNTs) plays a crucial role for the optical assignment and the estimation of the abundance of a given nanotube species in a sample. In particular, pronounced absorption intensities do not necessarily correspond to a high abundance in the investigated sample. Based on a microscopic approach, we calculate excitonic absorption spectra for a variety of semiconducting and metallic CNTs allowing us to investigate the diameter and the chirality dependence of the oscillator strength for individual carbon nanotubes [1,2]. Our calculations reveal a pronounced chiral dependence, which strongly varies for different optical transitions and nanotube families. We find that semiconducting CNTs with large chiral angles (armchair-like) and large diameters show the most pronounced absorption intensities confirming the experimentally observed trend [3].

[1] Eike Verdenhalven and Ermin Malic, "Excitonic oscillator strength of metallic and semiconducting carbon nanotubes", submitted for publication (2012)

[2] Ermin Malic, Janina Maultzsch, Stephanie Reich, and Andreas Knorr, Phys. Rev. B 82, 035433 (2010)

[3] S. M. Bachilo et al., Science 298, 2361 (2002); Y. Miyauchi et al., Chem. Phys. Lett. 387, 198 (2004)