Top-gate defined double quantum dots in InAs nanowires

TL;DR

This paper demonstrates the creation and control of double quantum dots in InAs nanowires using top-gates without additional insulators, revealing tunable coupling and molecular states through low-temperature transport measurements.

Contribution

It introduces a novel method to define double quantum dots in InAs nanowires with full tunability of inter-dot coupling without extra insulating layers.

Findings

Achieved full tunability from strong to weak coupling.

Observed molecular states extending over both dots.

Detected excitation spectra via nonlinear transport.

Abstract

We present low temperature transport measurements on double quantum dots in InAs nanowires grown by metal-organic vapor phase epitaxy. Two dots in series are created by lithographically defined top-gates with a procedure involving no extra insulating layer. We demonstrate the full tunability from strong to weak coupling between the dots. The quantum mechanical nature of the coupling leads to the formation of a molecular state extending over both dots. The excitation spectra of the individual dots are observable by their signatures in the nonlinear transport.