Two path transport measurements on a triple quantum dot

TL;DR

This paper reports on a sophisticated triple quantum dot device enabling multi-path transport measurements and charge detection, revealing detailed quantum states and resonance conditions among the dots.

Contribution

It introduces a novel triple quantum dot setup with starlike geometry and dual-path transport measurement capabilities, including charge detection with a quantum point contact.

Findings

Observation of clear signatures of individual dot states.

Resonances allowing serial transport along two-dot paths.

Analysis of quadruple points with all three dots in resonance.

Abstract

We present an advanced lateral triple quantum dot made by local anodic oxidation. Three dots are coupled in a starlike geometry with one lead attached to each dot thus allowing for multiple path transport measurements with two dots per path. In addition charge detection is implemented using a quantum point contact. Both in charge measurements as well as in transport we observe clear signatures of states from each dot. Resonances of two dots can be established allowing for serial transport via the corresponding path. Quadruple points with all three dots in resonance are prepared for different electron numbers and analyzed concerning the interplay of the simultaneously measured transport along both paths.