Lissajous rocking ratchet

TL;DR

This paper introduces a Lissajous rocking ratchet that uses broken time-reversal symmetry in a quantum dot system to control electron tunneling direction via frequency and phase modulation, with broad potential applications.

Contribution

It presents the first experimental realization and theoretical analysis of a Lissajous rocking ratchet based on modulated quantum dot barriers, demonstrating controlled electron transport without net bias.

Findings

Controlled electron tunneling direction via phase and frequency modulation.

Experimental verification of the Lissajous ratchet concept.

Potential for implementation in various nano-electronic systems.

Abstract

Breaking time-reversal symmetry (TRS) in the absence of a net bias can give rise to directed steady-state non-equilibrium transport phenomena such as ratchet effects. Here we present, theoretically and experimentally, the concept of a Lissajous rocking ratchet as an instrument based on breaking TRS. Our system is a semiconductor quantum dot (QD) 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 nano-electrical, nano-electromechanical or superconducting circuits. It promises applications based on a detailed on-chip comparison of radio-frequency signals.