Enhancing polarization transfer from nitrogen-vacancy centers in diamond to external nuclear spins via dangling bond mediators

TL;DR

This paper proposes a method to improve the transfer of polarization from nitrogen-vacancy centers in diamond to external nuclear spins by using dangling bonds as mediators, enhancing NMR sensitivity.

Contribution

It introduces a novel approach leveraging existing microwave sequences and surface defects to facilitate efficient polarization transfer in realistic conditions.

Findings

Demonstrates polarization transfer via dangling bonds

Achieves increased polarization rates under practical conditions

Utilizes PulsePol sequence for robust transfer

Abstract

The use of nitrogen-vacancy centers in diamond as a non-invasive platform for hyperpolarizing nuclear spins in molecular samples is a promising area of research with the potential to enhance the sensitivity of nuclear magnetic resonance experiments. Transferring NV polarization out of the diamond structure has been achieved on nanoscale targets using dynamical nuclear polarization methods, but extending this to relevant NMR volumes poses significant challenges. One major technical hurdle is the presence of paramagnetic defects in the diamond surface which can interfere with polarization outflow. However, these defects can also be harnessed as intermediaries for the interaction between NVs and nuclear spins. We present a method that benefits from existing microwave sequences, namely the PulsePol, to transfer polarization efficiently and robustly using dangling bonds or other localized electronic spins, with the potential to increase polarization rates under realistic conditions.