g-Tensor Control in Bent Carbon Nanotube Quantum Dots

TL;DR

This paper demonstrates gate-controlled manipulation of the electronic g-tensor in bent carbon nanotube quantum dots, enabling precise control of spin properties for quantum computing applications.

Contribution

It introduces a method to control the g-tensor via gate voltages in bent carbon nanotube quantum dots, combining spectroscopic and conductance measurements.

Findings

Gate control of the g-tensor is achieved and characterized.

Spin-orbit and valley couplings are quantified.

The positions of quantum dots are inferred from magnetic field dependence.

Abstract

We demonstrate gate control of the electronic g-tensor in single and double quantum dots formed along a bend in a carbon nanotube. From the dependence of the single-dot excitation spectrum on magnetic field magnitude and direction, we extract spin-orbit coupling, valley coupling, spin and orbital magnetic moments. Gate control of the g-tensor is measured using the splitting of the Kondo peak in conductance as a sensitive probe of Zeeman energy. In the double quantum dot regime, the magnetic field dependence of the position of cotunneling lines in the two dimensional charge stability diagram is used to infer the positions of the two dots along the nanotube.