Spin-dependent Quantum Interference in Single-Wall Carbon Nanotubes with Ferromagnetic Contacts

TL;DR

This paper demonstrates spin-dependent quantum interference effects in single-wall carbon nanotubes with ferromagnetic contacts, showing gate-dependent magnetoresistance oscillations and bias effects consistent with quantum transport models.

Contribution

First experimental observation of spin-induced magnetoresistance oscillations in carbon nanotubes with ferromagnetic contacts, validated by theoretical modeling.

Findings

Magnetoresistance oscillates with gate voltage.

Bias induces oscillations related to nanotube level spacing.

High bias reduces spin polarization and magnetoresistance.

Abstract

We report the experimental observation of spin-induced magnetoresistance in single-wall carbon nanotubes contacted with high-transparency ferromagnetic electrodes. In the linear regime the spin-induced magnetoresistance oscillates with gate voltage in quantitative agreement with calculations based on a Landauer-Buttiker model for independent electrons. Consistent with this interpretation, we find evidence for bias-induced oscillation in the spin-induced magnetoresistance signal on the scale of the level spacing in the nanotube. At higher bias, the spin-induced magnetoresistance disappears because of a sharp decrease in the effective spin-polarization injected from the ferromagnetic electrodes.