One-way transport in quantum dots
M. Blaauboer · Physics World · 2002
Rectifiers are devices that only allow movement in one direction. Examples include self-winding wristwatches and rectifiers in electrical circuits. Even though the exact mechanism is different for each, all rectifiers share a common principle: the rectification is based on an asymmetry in the system that makes it much easier for motion to occur in one direction than another.