Intraband electron focusing in bilayer graphene

TL;DR

This paper proposes a valley-selective Veselago lens in bilayer graphene, demonstrating negative refraction and coherent electron focusing influenced by band structure and mechanical strain.

Contribution

It introduces a novel method for electron focusing in bilayer graphene using band structure engineering and external strain control.

Findings

Negative refraction achieved in bilayer graphene

Interference pattern controllable by mechanical strain

Potential for valley-selective electronic devices

Abstract

We propose an implementation of a valley selective electronic Veselago lens in bilayer graphene. We demonstrate that in the presence of an appropriately oriented potential step, low-energy electrons radiating from a point source can be re-focused coherently within the same band. The phenomenon is due to the trigonal warping of the band structure that leads to a negative refraction index. We show that the interference pattern can be controlled by an external mechanical strain.