# Oxygenated (113) diamond surface for nitrogen-vacancy quantum sensors with preferential alignment and long coherence time from first principles

## TL;DR

This study uses first principles calculations to identify oxygenated (113) diamond surfaces as ideal hosts for shallow NV centers, offering positive electron affinity, minimal strain, and high NV alignment, enhancing quantum sensing performance.

## Contribution

It demonstrates that oxygen termination on (113) diamond surfaces creates favorable conditions for NV centers, surpassing other surfaces like (001) and (111) in coherence and alignment.

## Key findings

- Oxygenated (113) diamond has positive electron affinity.
- Oxygen termination causes minimal surface strain.
- High NV center alignment (~73%) on (113) diamond enhances sensing.

## Abstract

Shallow nitrogen-vacancy (NV) center in diamond is promising in quantum sensing applications however its sensitivity has been limited by surface terminators and defects. There is an immediate quest to find suitable diamond surfaces for NV sensors. In this work, the surface terminators of (113) diamond to host shallow NV centers are studied by means of first principles calculations. Results indicate that complete oxygen termination of (113) diamond creates positive electron affinity with neither strain on the surface nor in-gap levels. This is a very surprising result as the commonly employed oxygenated (001) diamond surface is often defective due to the disorder created by the strain of ether groups at the surface that seriously undermine the coherence properties of the shallow NV centers. The special atomic configurations on (113) diamond surface are favorable for oxygen bonding, in contrast to (001) and (111) diamond surfaces. These simulations imply that oxygenated diamond (113) surface can be produced by conventional diamond chemical vapor deposition growth. Combining this with the ~73% preferential alignment of as-grown NV centers in (113) oriented diamond, oxygenated (113) diamond is presently supposed to be the most prospective host for NV quantum sensors.

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Source: https://tomesphere.com/paper/1901.11170