# Microscopic imaging of elastic deformation in diamond via in-situ stress tensor sensors

## TL;DR

This paper introduces a novel method using nitrogen-vacancy defects in diamond to map the full stress tensor at the nanoscale with high sensitivity, enabling detailed analysis of mechanical stresses in various materials and devices.

## Contribution

The authors develop and demonstrate a technique for spatially mapping the complete stress tensor in diamond using atomic-sized in-situ strain sensors, achieving sub-micrometer resolution and high sensitivity.

## Key findings

- Successful mapping of elastic stress in diamond from implantation damage, nano-indents, and scratches.
- Detection of large stress contributions from electronic devices on diamond.
- Sensitivity to deformations in materials contacting the diamond.

## Abstract

The precise measurement of mechanical stress at the nanoscale is of fundamental and technological importance. In principle, all six independent variables of the stress tensor, which describe the direction and magnitude of compression/tension and shear stress in a solid, can be exploited to tune or enhance the properties of materials and devices. However, existing techniques to probe the local stress are generally incapable of measuring the entire stress tensor. Here, we make use of an ensemble of atomic-sized in-situ strain sensors in diamond (nitrogen-vacancy defects) to achieve spatial mapping of the full stress tensor, with a sub-micrometer spatial resolution and a sensitivity of the order of 1 MPa (corresponding to a strain of less than $10^{-6}$). To illustrate the effectiveness and versatility of the technique, we apply it to a broad range of experimental situations, including mapping the elastic stress induced by localized implantation damage, nano-indents and scratches. In addition, we observe surprisingly large stress contributions from functional electronic devices fabricated on the diamond, and also demonstrate sensitivity to deformations of materials in contact with the diamond. Our technique could enable in-situ measurements of the mechanical response of diamond nanostructures under various stimuli, with potential applications in strain engineering for diamond-based quantum technologies and in nanomechanical sensing for on-chip mass spectroscopy.