Regensburg 2016 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 11: Focus Session: Single Particle Sources for Electronic Devices II
(Joint session of HL and TT organized by HL)

TT 11.6: Vortrag

Montag, 7. März 2016, 17:15–17:30, H10

Lissajous Rocking Ratchet: Realization in a Semiconductor Quantum Dot — •Sergey Platonov^1,2, Bernd Kästner³, Hans W. Schumacher³, Sigmund Kohler⁴, and Stefan Ludwig^1,2 — ¹Center for NanoScience & Fakultät für Physik, LMU-Munich, 80539 München, Germany — ²Paul-Drude-Institut für Festkörperphysik, Hausvogteiplatz 5-7 10117 Berlin, Germany — ³Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany — ⁴Instituto de Ciencia de Materiales de Madrid, CSIC, 28049 Madrid, Spain

Symmetries are a very important concept of physics - the most famous one being the CPT symmetry. Breaking symmetries often gives rise to interesting effects and, in particular, breaking the time-reversal symmetry is a requirement for many applications such as information processing. Here we present such a concept based on a quantum dot (QD) electrostatically defined in a AlGaAs/GaAs heterostructure. We break time-reversal symmetry by periodically modulating its barriers such that a single electron tunneling current occurs. The current direction can be controlled by introducing a phase difference between the two periodic signals. We show that our QD resembles a Lissajous rocking ratchet. A consistent theoretical model based on scattering matrix formalism describes our experimental findings. Similar devices could be realized in a large variety of systems, for instance in nanomechanical or superconducting circuits. Possible applications include noise management, filtering and signal routing.