Tunable double quantum dots in InAs nanowires

Abstract

Semiconductor nanowires offer a very versatile approach to create tunable quantum dots. Of the different semiconductor materials that can be grown as nanowires, InAs is particularly interesting due to the large spin–orbit coupling and furthermore promising for devices due to the comparably easy processing for Ohmic contacts. Here we study the electronic transport through gateable InAs nanowire devices at low temperatures. The nanowires are grown by MOVPE, and horizontal devices are individually fabricated using electron-beam lithography. We use local top gates to create barriers that can be used to define tunable quantum dots. Towards our final goal of spin manipulation of single electrons, we focus on tunable double dots. We measure the electronic transport through double quantum dots for the different accessible regimes: we present stability diagrams that demonstrate the tunability from two independent dots to one combined dot, including the particularly interesting region of two interacting quantum dots.