Electron quantum ratchets

Ratchets are spatially asymmetric devices in which directed particle flow can occur due to the rectification of fluctuations, in the absence of external net forces or gradients. In this paper we point out that mesoscopic semiconductor structures are ideally suited systems for the study of quantum ratchet effects. As an example, we present experimental and theoretical data showing that phase coherent, asymmetric electron cavities can partially rectify an applied AC voltage.