title: Lissajous Rocking Ratchet: Realization in a Semiconductor Quantum Dot.
abstract: Breaking time-reversal symmetry (TRS) in the absence of a net bias can give rise to directed steady-state nonequilibrium transport phenomena such as ratchet effects. Here we present, theoretically and experimentally, the concept of a Lissajous rocking ratchet based on breaking TRS. Our system is a semiconductor quantum dot with periodically modulated dot-lead tunnel barriers. Broken TRS gives rise to single electron tunneling current. Its direction is fully controlled by exploring frequency and phase relations between the two barrier modulations. The concept of Lissajous ratchets can be realized in a large variety of different systems, including nanoelectrical, nanoelectromechanical, or superconducting circuits. It promises applications based on a detailed on-chip comparison of radio-frequency signals.
authors.affiliation: Center for NanoScience and Fakultät für Physik, LMU-Munich, 80539 München, Germany.
authors.forename: Sergey
authors.initials: S
authors.lastname: Platonov
authors.affiliation: Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany.
authors.forename: Bernd
authors.initials: B
authors.lastname: Kästner
authors.affiliation: Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany.
authors.forename: Hans W
authors.initials: HW
authors.lastname: Schumacher
authors.affiliation: Instituto de Ciencia de Materiales de Madrid, CSIC, 28049 Madrid, Spain.
authors.forename: Sigmund
authors.initials: S
authors.lastname: Kohler
authors.affiliation: Center for NanoScience and Fakultät für Physik, LMU-Munich, 80539 München, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Ludwig