Regensburg 2016 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 84: Novel Functional Materials I
HL 84.7: Vortrag
Donnerstag, 10. März 2016, 17:00–17:15, H17
Electronic structure calculations for carbon nanotubes under strain — •Christian Wagner1,3, Jörg Schuster2, Michael Schreiber3, Andre Schleife4, and Thomas Gessner1,2 — 1Center for Microtechnologies, TU Chemnitz, Germany — 2Fraunhofer Institute ENAS, Chemnitz, Germany — 3Institute of Physics, TU Chemnitz, Germany — 4Department for Materials Science, University of Illinois at Urbana-Champaign, USA
Carbon nanotube (CNT) optics is an active field of research and is becoming increasingly interesting for applications. CNTs show unique properties upon strain: Under load, their band gap is opening or closing (depending on the CNTs’ chirality) which makes them suitable for electronic and optical strain sensing at the nano scale. Further, they could operate as strain-tunable emitters.
We present results of electronic structure calculations for strained CNTs: we employ density functional theory (DFT) for ground states, GW approximation for a correct description of the fundamental gap, and we solve the Bethe-Salpeter-equation for the optical polarization function.
Our results are strain-dependent band gaps and the derived deformation potentials for different CNT chiralities. The strain-induced shift of exciton-related peaks is quantified. This requires cutting off the Coulomb interaction of periodic images in our supercell approach. The strain parameters derived here can be used for large-scale device modeling and is compared to available literature data.