Radiation-induced current in quantum wires with side-coupled nano-rings

TL;DR

This study investigates how a quantum wire with side-coupled nano-rings generates photocurrent when illuminated with circularly polarized light, revealing geometry-dependent and interference effects that enable scalable nanoscale current sources.

Contribution

It introduces a novel system combining quantum wires and rings to produce photocurrent, highlighting the role of geometry and polarization in current generation.

Findings

Photocurrent depends on the number of rings and system parameters.

Current arises due to broken time-reversal symmetry from circular polarization.

Quantum interference causes a weak non-linear relation between rings and current.

Abstract

Photocurrent generation is studied in a system composed of a quantum wire with side-coupled quantum rings. The current generation results from the interplay of the particular geometry of the system and the use of circularly polarized radiation. We study the energy-momentum conservation for optical transitions involving electrons moving forwards and backwards in the wire. Due to the lack of time-reversal symmetry in the radiation, the optical transitions depend on the direction of motion of the electrons, leading to a current at zero bias voltage. The photocurrent increases with the number of rings within a wide range of physical parameters. A weak non-linear dependence of the current in the number of rings, related to quantum interference effects, is also predicted. This geometry suggests a scalable method for the generation of sizeable photocurrents based on nanoscale components.