A 50/50 electronic beam splitter in graphene nanoribbons as a building block for electron optics

TL;DR

This paper proposes a graphene nanoribbon-based 50/50 electronic beam splitter that operates without large magnetic fields or ultra-low temperatures, using atomistic modeling to demonstrate its robustness and potential for electron optics applications.

Contribution

It introduces a novel graphene nanoribbon setup functioning as a perfect, switchable 50/50 electron beam splitter, robust against disorder and thermal effects.

Findings

Achieves 50/50 splitting without magnetic fields or ultra-low temperatures.

Operation controlled by Fermi energy doping.

Device is robust against disorder and thermal fluctuations.

Abstract

Based on the investigation of the multi-terminal conductance of a system composed of two graphene nanoribbons, in which one is on top of the other and rotated by 60 degrees, we propose a setup for a 50/50 electronic beam splitter that neither requires large magnetic fields nor ultra low temperatures. Our findings are based on an atomistic tight-binding description of the system and on the Green's function method to compute the Landauer conductance. We demonstrate that this system acts as a perfect 50/50 electronic beam splitter, in which its operation can be switched on and off by varying the doping (Fermi energy). We show that this device is robust against thermal fluctuations and long range disorder, as zigzag valley chiral states of the nanoribbons are protected against backscattering. We suggest that the proposed device can be applied as the fundamental element of the Hong-Ou-Mandel interferometer, as well as a building block of many devices in electron optics.