Double quantum dot with tunable coupling in an enhancement-mode silicon metal-oxide semiconductor device with lateral geometry

TL;DR

This paper reports on a silicon double quantum dot device with lateral geometry, demonstrating tunable interdot coupling and symmetry properties, supported by experimental measurements and numerical simulations.

Contribution

It introduces a tunable silicon double quantum dot device with lateral geometry and shows how gate voltages can control interdot coupling despite intrinsic asymmetries.

Findings

Device exhibits large symmetry under gate voltages

Gate voltages offset intrinsic device asymmetry

Transition from single dot to coupled double dots controlled by central gate

Abstract

We present transport measurements of a tunable silicon metal-oxide-semiconductor double quantum dot device with lateral geometry. Experimentally extracted gate-to-dot capacitances show that the device is largely symmetric under the gate voltages applied. Intriguingly, these gate voltages themselves are not symmetric. Comparison with numerical simulations indicates that the applied gate voltages serve to offset an intrinsic asymmetry in the physical device. We also show a transition from a large single dot to two well isolated coupled dots, where the central gate of the device is used to controllably tune the interdot coupling.