Dynamic Acoustic Control of Individual Optically Active Quantum Dot-like   Emission Centers in Heterostructure Nanowires
  We probe and control the optical properties of emission centers forming in radial het- erostructure GaAs-Al0.3Ga0.7As nanowires and show that these emitters, located in Al0.3Ga0.7As layers, can exhibit quantum-dot like characteristics. We employ a radio frequency surface acoustic wave to dynamically control their emission energy and occupancy state on a nanosec- ond timescale. In the spectral oscillations we identify unambiguous signatures arising from both the mechanical and electrical component of the surface acoustic wave. In addition, differ- ent emission lines of a single quantum dot exhibit pronounced anti-correlated intensity oscilla- tions during the acoustic cycle. These arise from a dynamically triggered carrier extraction out of the quantum dot to a continuum in the radial heterostructure. Using finite element modeling and Wentzel-Kramers-Brillouin theory we identify quantum tunneling as the underlying mech- anism. These simulation results quantitatively reproduce the observed switching and show that in our systems these quantum dots are spatially separated from the continuum by > 10.5 nm. 
Matthias Wei{\ss}, J\"org B. Kinzel, Florian J. R. Sch\"ulein, Michael   Heigl, Daniel Rudolph, Stefanie Mork\"otter, Markus...
cond-mat.mes-hall cond-mat.mtrl-sci physics.optics quant-ph