Berlin 2018 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 37: Oxide Semiconductors

HL 37.9: Vortrag

Donnerstag, 15. März 2018, 11:45–12:00, EW 203

Interactions of Rydberg Excitons in Cu₂O — •Felix Föst¹, Julian Heckötter¹, Rico Schwartz^2,1, Marc Aßmann¹, Dietmar Fröhlich¹, and Manfred Bayer¹ — ¹Experimentelle Physik 2, TU Dortmund, Germany — ²Institut für Physik, Universität Rostock, Germany

In this work we present absorption measurements on highly excited Rydberg excitons in cuprous oxide with principal quantum numbers n up to 25 and odd angular momentum (p, f,…, in analogy to the hydrogen atom). These excitons have a large orbital extension of up to 2 microns [1], covering over 10⁹ unit cells, which leads to a strong dipole moment and therefore a giant dipole-dipole interaction.

We investigate the interaction of these highly excited Rydberg states with other exciton states, e.g. p-excitons with low n or the 1s exciton. To accomplish this, we use 2 CW lasers in a conventional two-colour pump-probe setup to pump different fixed exciton resonances and simultaneously probe the absorption spectrum. With increasing pump laser power density, we find a decrease of absorption efficiency for large quantum numbers n in accordance with theory [1]. In addition, we also see an initial increase in absorption for small n for both p- and f-excitons, which is larger for higher pump energies.

[1] T. Kazimierczuk et al., Nature 514, (2014), p. 343