Imaging of double slit interference by scanning gate microscopy

TL;DR

This paper investigates the capability of scanning gate microscopy to image double slit interference in a quantum point contact system, revealing conditions under which interference patterns are observable or hidden in conductance measurements.

Contribution

The study provides a theoretical analysis explaining why interference patterns are often absent in conductance maps and proposes a setup geometry for observing double slit interference.

Findings

Interference is visible in scattered wave functions but often missing in conductance maps.

The Landauer approach explains the absence of interference in measurements.

A geometry setup is proposed to enable observation of the interference.

Abstract

We consider scanning gate microscopy imaging of the double slit interference for a pair of quantum point contacts (QPCs) defined within the two-dimensional electron gas. The interference is clearly present in the scattered electron wave functions for each of the incident subbands. Nevertheless, we find that the interference is generally missing in the experimentally accessible conductance maps for many incident subbands. We explain this finding on the basis of the Landauer approach. A setup geometry allowing for observation of the double slit interference by the scanning gate microscopy is proposed.