Non-flipping 13C spins in NV diamond: Hyperfine and Spatial Characteristics by DFT Simulation of the C510[NV]H252 Cluster

TL;DR

This study uses DFT simulations to identify stable NV-13C nuclear spin systems in diamond, revealing new non-axial configurations with negligible flip-flop rates, some of which align with experimental observations, advancing quantum memory research.

Contribution

The paper introduces a systematic DFT-based approach to identify stable NV-13C complexes, discovering new non-axial configurations with minimal flip-flop rates not previously reported.

Findings

Identified stable NV-13C systems with negligible hyperfine-induced flip-flops.

Discovered new non-axial 13C positions in the diamond lattice.

Experimental confirmation of some predicted non-axial systems.

Abstract

Single NV centers in diamond coupled by hyperfine interaction to neighboring 13C nuclear spins are now widely used in the emerging quantum technologies as elements of quantum memory adjusted to NV center electron spin qubit. For nuclear spins with low flip-flop rate, single shot readout was demonstrated under ambient conditions. Here we report on the systematic search of such stable NV-13C systems using density functional theory (DFT) to simulate hyperfine and spatial characteristics of all possible NV-13C complexes in the H-terminated cluster C510 [NV]-H252 hosting the NV center. Along with the expected stable NV- axial 13C systems wherein the 13C nuclear spin is located on the NV axis, we found for the first time new families of positions for the 13C nuclear spin exhibiting negligible hyperfine-induced flipping rates due to near-symmetric local spin density distribution. Spatially, these positions are located in the diamond bilayer passing through the vacancy of the NV center and being perpendicular to the NV axis. Analysis of available publications showed that, apparently, some of the predicted non-axial near-stable systems NV-13C have already been observed experimentally. A special experiment done on one of these systems confirmed the prediction made