Orbital Tuning of Tunnel Coupling in InAs/InP Nanowire Quantum Dots

TL;DR

This paper demonstrates how electrostatic gating can control tunnel coupling in InAs/InP nanowire quantum dots by tuning orbital configurations, enabling precise manipulation of tunneling rates for quantum device applications.

Contribution

It reveals a new regime where tunneling is governed by orbital axial configuration at low filling, and shows how radial orbital control further modulates barrier transparency.

Findings

Tunneling rates depend on orbital axial configuration at low filling.

Electrostatic gating modifies radial orbital configurations and transmission rates.

Barrier transparency evolves as predicted by numerical simulations.

Abstract

We report results on the control of barrier transparency in InAs/InP nanowire quantum dots via the electrostatic control of the device electron states. Recent works demonstrated that barrier transparency in this class of devices displays a general trend just depending on the total orbital energy of the trapped electrons. We show that a qualitatively different regime is observed at relatively low filling numbers, where tunneling rates are rather controlled by the axial configuration of the electron orbital. Transmission rates versus filling are further modified by acting on the radial configuration of the orbitals by means of electrostatic gating, and the barrier transparency for the various orbitals is found to evolve as expected from numerical simulations. The possibility to exploit this mechanism to achieve a controlled continuous tuning of the tunneling rate of an individual Coulomb blockade resonance is discussed.