Observation of Pure Spin Transport in a Diamond Spin Wire

TL;DR

This paper demonstrates direct measurement of pure spin transport in a diamond spin wire, revealing a spin diffusion length of approximately 700 nm, using magnetic resonance techniques to analyze nanoscale spin dynamics without charge movement.

Contribution

The study provides the first direct measurement of pure spin transport in a nanoscale diamond spin wire, utilizing statistical fluctuations and magnetic resonance for detailed spin dynamics analysis.

Findings

Spin diffusion length ~700 nm in diamond spin wire

Pure spin transport achieved without charge motion

Magnetic resonance enhances spatial resolution and spectroscopic insights

Abstract

Spin transport electronics - spintronics - focuses on utilizing electron spin as a state variable for quantum and classical information processing and storage. Some insulating materials, such as diamond, offer defect centers whose associated spins are well-isolated from their environment giving them long coherence times; however, spin interactions are important for transport, entanglement, and read-out. Here, we report direct measurement of pure spin transport - free of any charge motion - within a nanoscale quasi 1D 'spin wire', and find a spin diffusion length ~ 700 nm. We exploit the statistical fluctuations of a small number of spins ($\sqrt{N}$ < 100 net spins) which are in thermal equilibrium and have no imposed polarization gradient. The spin transport proceeds by means of magnetic dipole interactions that induce flip-flop transitions, a mechanism that can enable highly efficient, even reversible, pure spin currents. To further study the dynamics within the spin wire, we implement a magnetic resonance protocol that improves spatial resolution and provides nanoscale spectroscopic information which confirms the observed spin transport. This spectroscopic tool opens a potential route for spatially encoding spin information in long-lived nuclear spin states. Our measurements probe intrinsic spin dynamics at the nanometre scale, providing detailed insight needed for practical devices which seek to control spin.