Coherent Transport Through a Quadruple Point in a Few Electron Triple Dot

TL;DR

This paper demonstrates coherent electron transport through a triple quantum dot at quadruple resonance points, confirmed by phase shifts in magneto-conductance oscillations, advancing quantum dot control techniques.

Contribution

It reports the first observation of coherent transport at quadruple points in a triple quantum dot system, using charge detection and magneto-transport measurements.

Findings

Coherent transport confirmed by Pi phase shift in oscillations

Achievement of quadruple points with all three dots on resonance

Demonstration of control over multi-dot quantum states

Abstract

A few electron double electrostatic lateral quantum dot can be transformed into a few electron triple quantum dot by applying a different combination of gate voltages. Quadruple points have been achieved at which all three dots are simultaneously on resonance. At these special points in the stability diagram four occupation configurations are possible. Both charge detection and transport experiments have been performed on this device. In this short paper we present data and confirm that transport is coherent by observing a Pi phase shift in magneto-conductance oscillations as one passes through the quadruple point.