Deterministic Creation of Strained Color Centers in Nanostructures via High-Stress Thin Films

TL;DR

This paper demonstrates a scalable method to create highly strained silicon-vacancy color centers in diamond nanostructures using high-stress thin films, enabling operation at higher temperatures for quantum memory applications.

Contribution

It introduces a reproducible technique combining high-stress silicon nitride films with diamond nanostructures to produce strained color centers with potential for high-temperature quantum operation.

Findings

Strain of ~4 x 10^{-4} achieved in silicon-vacancy centers.

Mean ground state splitting of 608 GHz observed.

Strained centers operate at temperatures above 1K without decoherence.

Abstract

Color centers have emerged as a leading qubit candidate for realizing hybrid spin-photon quantum information technology. One major limitation of the platform, however, is that the characteristics of individual color-centers are often strain dependent. As an illustrative case, the silicon-vacancy center in diamond typically requires millikelvin temperatures in order to achieve long coherence properties, but strained silicon vacancy centers have been shown to operate at temperatures beyond 1K without phonon-mediated decoherence. In this work we combine high-stress silicon nitride thin films with diamond nanostructures in order to reproducibly create statically strained silicon-vacancy color centers (mean ground state splitting of 608 GHz) with strain magnitudes of $\sim 4 \times 10^{-4}$. Based on modeling, this strain should be sufficient to allow for operation of a majority silicon-vacancy centers within the measured sample at elevated temperatures (1.5K) without any degradation of their spin properties. This method offers a scalable approach to fabricate high-temperature operation quantum memories. Beyond silicon-vacancy centers, this method is sufficiently general that it can be easily extended to other platforms as well.