Dresden 2020 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 79: Quantum dots and wires IV
HL 79.9: Talk
Friday, March 20, 2020, 11:45–12:00, POT 151
Quantum Dot Optomechanics In Suspended Nanophononic Strings — •BENJAMIN MAYER1, ANJA VOGELE1, MAXIMILIAN M. SONNER1, XUEYONG YUAN1,2, MATTHIAS WEISS1, EMELINE D. S. NYSTEN1, SAIMON F. COVRE DA SILVA2, ARMANDO RASTELLI2, and HUBERT J. KRENNER1 — 1Lehrstuhl für Experimentalphysik 1, Universität Augsburg, 86159 Augsburg, Germany — 2Institute of Semiconductor and Solid State Physics, Johannes Kepler Universität Linz, 4040 Linz, Austria
The optomechanical coupling of quantum dots and flexural mechanical modes is studied in suspended nanophononic strings. The investigated devices are designed and monolithically fabricated on an (Al)GaAs heterostructure. Radio frequency elastic waves with frequencies ranging between f = 250 and 400 MHz are generated as Rayleigh surface acoustic waves (SAW) on the unpatterned substrate and injected as Lamb waves in the nanophononic string. Quantum dots inside the nanophononic string exhibit a 15-fold enhanced optomechanical modulation compared to those dynamically strained by the SAW. Finite element simulations of the phononic mode spectrum of the nanophononic string confirm that the observed modulation arises from valence band deformation potential coupling via shear strain. The corresponding optomechanical coupling parameter is quantified to 0.15 meV nm-1. Using this value, a derived vertical displacement in the range of 10 nm is deduced from the experimental data. (Vogele et al., Adv. Quantum Tech. early view (2019). doi: 10.1002/qute.201900102)