Shaping Charge Excitations in Chiral Edge States with a Time-Dependent Gate Voltage

In this communication, we address the question of how the controlled injection of quantized charge excitations into a nanoscopic system is achieved, when a local emission is favored, but at the same time a strong size-confinement is hindered. Specifically, we propose an emission scheme, enabling a controlled production of noiseless, single-electron (and hole) current pulses by means of local time-dependent driving of a gate potential applied to a chiral edge transport channel. Employing a fully self-consistent treatment based on Floquet scattering theory, we study the effect of different voltage shapes and frequencies, as well as the role of the gate geometry on the injected signal. We highlight the impact of frequency-dependent screening on the process of shaping the current signal. The feasibility of creating true single-particle excitations with this method is confirmed by investigating the suppression of excess noise, which is otherwise created by additional electron-hole pair excitations in the current signal. Our analysis of the time-dependent transport in all driving-frequency regimes provides a clear recipe for the appropriate design of the gate-driving signal for local single-particle injection.

M. Misiorny, G. Fève, and J. Splettstoesser, arXiv:1711.00119 (in review)