Abstract
We study the appearance of directed current in tunnel junctions (quantum ratchet effect), in the presence of an external ac field $f(t).$ The current is established in a one-dimensional discrete inhomogeneous ``tight-binding model.'' By making use of a symmetry analysis we predict the right choice of $f(t)$ and obtain the directed current as a difference between electron transmission coefficients in opposite directions, $\ensuremath{\Delta}{T=T}^{\mathrm{LR}}\ensuremath{-}{T}^{\mathrm{RL}}.$ Numerical simulations confirm the predictions of the symmetry analysis and moreover, show that the directed current can be drastically increased by a proper choice of frequency and amplitudes of the ac field $f(t).$
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
