Berlin 2018 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

TT: Fachverband Tiefe Temperaturen

TT 33: Nanotubes and Nanoribbons

TT 33.7: Vortrag

Dienstag, 13. März 2018, 11:00–11:15, H 0110

Dark states in a carbon nanotube quantum dot - experiment — Michael Niklas¹, Michael Schafberger², Andrea Donarini¹, •Nicola Paradiso², Christoph Strunk², and Milena Grifoni¹ — ¹Institute of Theoretical Physics, University of Regensburg, 93053 Regensburg, Germany — ²Institute of Experimental and Applied Physics, University of Regensburg, 93053 Regensburg, Germany

Illumination of three level atoms (λ-systems) by detuned lasers can pump electrons into a coherent superposition of hyperfine-split levels which can no longer absorb light. Because fluorescent light emission is then suppressed, the coherent superposition is known as a dark state. We report an all-electric analogue of this destructive interference effect in a carbon nanotube quantum dot. A dark state is in this case a coherent superposition of states with opposite angular momentum which is fully decoupled from either the drain or the source leads. The emergence of dark states impacts the current-voltage characteristics, where missing current steps are observed depending on the sign of the applied source-drain bias. Our results demonstrate for the first time coherent-population trapping by all-electric means in an artificial atom.