# Transport through an AC driven impurity: Fano interference and bound states in the continuum

## TL;DR

This paper investigates how an AC-driven impurity affects electron transport in a tight-binding chain, revealing Fano resonances, bound states in the continuum, and the impact of driving parameters on transmission properties.

## Contribution

It provides exact, frequency- and amplitude-independent analysis of transport through an AC-driven impurity, highlighting the control of resonances and tunneling phenomena.

## Key findings

- Fano resonances occur at frequencies near the bandwidth.
- Resonance positions and widths can be tuned by driving parameters.
- High-frequency limit relates to coherent destruction of tunneling.

## Abstract

Using the Floquet formalism we study transport through an AC-driven impurity in a tight binding chain. The results obtained are exact and valid for all frequencies and barrier amplitudes. At frequencies comparable to the bulk bandwidth we observe a breakdown of the transmission $T=0$ which is related to the phenomenon of Fano resonances associated to AC-driven bound states in the continuum. We also demonstrate that the location and width of these resonances can be modified by tuning the frequency and amplitude of the driving field. At high frequencies there is a close relation between the resonances and the phenomenon of coherent destruction of tunneling. As the frequency is lowered no more resonances are possible below a critical value and the results approach a simple time average of the static transmission.