Demonstration of electron focusing using electronic lenses in low-dimensional system

Chengyu Yan,David Ritchie,Michael Pepper,Ian Farrer,Patrick See,Jonathan Griffiths

doi:10.1038/s41598-020-59453-x

Abstract

We report an all-electric integrable electron focusing lens in n-type GaAs. It is shown that a pronounced focusing peak takes place when the focal point aligns with an on-chip detector. The intensity and full width half maximum (FWHM) of the focusing peak are associated with the collimation of injected electrons. To demonstrate the reported focusing lens can be a useful tool, we investigate the characteristic of an asymmetrically gate biased quantum point contact with the assistance of a focusing lens. A correlation between the occurrence of conductance anomaly in low conductance regime and increase in FWHM of focusing peak is observed. The correlation is likely due to the electron-electron interaction. The reported electron focusing lens is essential for a more advanced electron optics device.

Highlights

We report an all-electric integrable electron focusing lens in n-type GaAs
It is well known that quantum point contacts (QPCs) or other low-dimensional electron sources are equivalent to a coherent optical source[8]; electronic spin polariser is inspired by an optical polariser[9]; electronic cavity/mirror shares functional similarities with the optical ones[10]
We have developed a double-convex electron focusing lens which is an essential component for a complete tool kit of electron optics

Summary

Introduction

We report an all-electric integrable electron focusing lens in n-type GaAs. It is shown that a pronounced focusing peak takes place when the focal point aligns with an on-chip detector. Before being collected at QPC3, collimated electrons pass through an electronic focusing lens defined via a top gate encapsulating a double-concave shaped hollow regime [Fig. 1(b); see Supplementary Information Note 1 and 2 for

Results

Conclusion