Coherent control of photoconductivity in graphene nanoribbons

TL;DR

This paper investigates how to control and enhance photoconductivity in graphene nanoribbons using polarized light and coherence effects, proposing a fast switching protocol and a heterostructure device for advanced electronics.

Contribution

It introduces a method to control photoconductivity in graphene nanoribbons via polarized light and coherence, including a fast switching protocol and a heterostructure transistor design.

Findings

Maximum photocurrent occurs near blue-detuned frequencies.

Coherent light enhances photoconductivity more than incoherent light.

Proposed heterostructure functions as a transistor for coherent electronics.

Abstract

We study the photoconductivity response of graphene nanoribbons with armchair edges in the presence of dissipation using a Lindblad-von Neumann master equation formalism. We propose to control the transport properties by illuminating the system with light that is linearly polarized along the finite direction of the nanoribbon while probing along the extended direction. We demonstrate that the largest steady-state photocurrent occurs for a driving frequency that is slightly blue-detuned to the electronic band gap proportional to the width of the nanoribbon. We compare the photoconductivity in the presence of coherent and incoherent light and conclude that the enhancement of the photoconductivity for blue-detuned driving relies on the coherence of the driving term. Based on this result we propose a switching protocol for fast control of the photocurrent on a time scale of a few picoseconds. Furthermore, we suggest a design for a heterostructure of a graphene nanoribbon and a high-Tc superconductor, that is operated as a transistor as a step towards next-generation coherent electronics.