Fermionic Lensing in Smooth Graphene P-N Junctions

TL;DR

This paper investigates electron wave focusing in smooth graphene p-n junctions, revealing that Klein tunneling causes additional image broadening while negative refraction persists, and develops a theory to quantify this effect.

Contribution

It provides a theoretical analysis of fermionic lensing in smooth graphene p-n junctions, highlighting differences from sharp junctions and quantifying image broadening due to Klein tunneling.

Findings

Negative refraction persists in smooth junctions

Klein tunneling causes additional image broadening

Developed a theory to estimate broadening effects

Abstract

Focusing of electron waves in graphene p-n junctions is a striking manifestation of fermionic negative refraction. We analyze lensing in smooth p-n junctions and find that it differs in several interesting ways from that in the previously studied sharp p-n junctions. Most importantly, while the overall negative-refraction behavior remains unchanged, the image at the focal point undergoes additional broadening due to Klein tunneling in the junction. We develop a theory of image broadening and estimate the effect for practically interesting system parameter values.