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HL: Fachverband Halbleiterphysik

HL 17: Materials and devices for quantum technology I

HL 17.7: Vortrag

Montag, 16. März 2020, 17:00–17:15, POT 112

Coherent 2D fluorescence spectroscopy on a single molecule indicates electron transfer related to the optical Gunn effect — •Matthias Nuß, Simon Büttner, Donghai Li, Friedrich Schöppler, Tobias Hertel, and Tobias Brixner — Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany

The Gunn effect [1] has changed daily lives through the use of "transferred-electron devices". Further developments would benefit from reduced dimensionalities (single-molecule transistors) with tunable quantized nonlinear electro-optical response. Special challenges are to overcome the "THz gap" and to access quantum effects at room temperature that are limited by ensemble averaging or lifetime. In this regard an optical Gunn behaviour was shown in Si nanowires and GaAs and proposed in single-walled carbon nanotubes (SWCNTs) [2]. We carried out ultrafast two-dimensional (2D) fluorescence spectroscopy [3] on an individual SWCNT. We provide insight into the spatio-temporal evolution of electron phonon-mediated intervalley and annihilation dynamics during ultrafast polaron decay in the phonon sideband of an individual SWCNT. We compare the temperature and power dependence, as well as the fourth-order 2D signal of the fluorescence with simulations, to identify the mechanism for electron transfer and discuss this in the light of the Gunn effect [1].
[1] J. B. Gunn, Solid State Commun. 1, 88-91 (1963).
[2] G. Pennington et al.,Phys. Rev. B 68, 045426 (2003)
[3] S. Goetz et al., Optics Express 26, Nr. 4: 3915-25 (2018).