Nanoscale electrical conductivity imaging using a nitrogen-vacancy center in diamond

TL;DR

This paper introduces a nanoscale conductivity imaging method using a nitrogen-vacancy center in diamond, enabling noninvasive, high-resolution, and quantitative magnetic fluctuation measurements of conductive materials.

Contribution

The authors develop a novel NV-center-based technique for nanoscale, noninvasive conductivity imaging with improved speed and resolution, expanding capabilities for condensed matter studies.

Findings

Achieved 40-nm spatial resolution in conductivity imaging.

Realized a 25-fold increase in imaging speed.

Demonstrated potential for imaging nanoscale phase separation in complex oxides.

Abstract

The electrical conductivity of a material can feature subtle, nontrivial, and spatially-varying signatures with critical insight into the material's underlying physics. Here we demonstrate a conductivity imaging technique based on the atom-sized nitrogen-vacancy (NV) defect in diamond that offers local, quantitative, and noninvasive conductivity imaging with nanoscale spatial resolution. We monitor the spin relaxation rate of a single NV center in a scanning probe geometry to quantitatively image the magnetic fluctuations produced by thermal electron motion in nanopatterned metallic conductors. We achieve 40-nm scale spatial resolution of the conductivity and realize a 25-fold increase in imaging speed by implementing spin-to-charge conversion readout of a shallow NV center. NV-based conductivity imaging can probe condensed-matter systems in a new regime, and as a model example, we project readily achievable imaging of nanoscale phase separation in complex oxides.