Tunable 0.7 conductance plateau in quantum dots

TL;DR

This paper demonstrates a tunable 0.7 conductance plateau in quantum dots, showing its evolution into an integer plateau and its persistence at very low temperatures, suggesting interference effects are important.

Contribution

It introduces a method to form and control the 0.7 structure in quantum dots, revealing new properties and emphasizing the role of electron interference.

Findings

0.7 structure can be tuned on and off in quantum dots.

The 0.7 plateau persists down to 100 mK with high flatness.

The 0.7 structure evolves into an integer conductance plateau.

Abstract

A consistent approach in forming the 0.7 structure by using a quantum dot rather than a quantum point contact is demonstrated. With this scheme, it was possible to tune on and off the 0.7 structure. The 0.7 structure continuously evolved into a normal integer conductance plateau by varying the tuning condition. Unlike the conventional 0.7 plateau, the new 0.7 structure was observed even at low electron temperatures down to 100 mK, with unprecedented flatness. From our results, it is concluded that electron interference should be taken into consideration to explain the 0.7 structure.