Nano-Ratchet sets free electrical power even without intentional excitation

Abstract

In theory ratchets enable energy harvesting by rectifying electrical fluctuations in conductors and semiconductors. Certain rectification effects in nanostructures have been demonstrated earlier. But these were not found to be usable for energy harvesting, as they were not accomplished by asymmetric transmission probabilities in the nanochannels, but rather by other secondary effects. We propose and experimentally prove a nano-ratchet effect directly linked to an asymmetry in the equilibrium transmission probability, which becomes possible when a magnetic field is present. Remarkably, the current/voltage do not disappear even without any intentional external excitation. The rectification is manifested to be highly efficient to the extent that generation of energy out of environmental electrical noises is achieved.