Rectification in Luttinger Liquids

We investigate the rectification of an ac bias in Luttinger liquids in the presence of an asymmetric potential (the ratchet effect). We show that a strong repulsive electron interaction enhances the ratchet current in comparison with Fermi-liquid systems, and the dc $I\mathrm{\text{−}}V$ curve is strongly asymmetric in the low-voltage regime even for a weak asymmetric potential. At higher voltages the ratchet current exhibits an oscillatory voltage dependence.

Figure 1

Density profiles averaged over the period of Friedel oscillations for a potential with $U_1<U_2$. The averaged densities show drops at the impurity positions.