Frequency scaling of photo-induced tunneling.

The DC current-voltage characteristics induced by a driving electric field with frequency Ω of a one-dimensional electron channel with a tunnel barrier is calculated. Electron-electron interaction of finite range is taken into account. For intermediate interaction strengths, the non-linear differential conductance shows cusp-like minima at bias voltages mΩ/e (m integer) that are a consequence of the finite non-zero range of the interaction but are independent of the shape of the driving electric field. However, the frequency-scaling of the photo-induced current shows a cross-over between Ω−1 and Ω−2, and depends on the spatial shape of the driving field and the range of the interaction.