Thin Film Lithium Niobate on Diamond (LiNDa) platform for Efficient Spin-Phonon Coupling

TL;DR

This paper introduces a novel thin-film lithium niobate on diamond platform that enhances spin-phonon coupling, enabling efficient acoustic control of SiV centers for quantum information applications.

Contribution

It presents the first heterogeneously integrated LiNbO3-diamond platform for strong spin-phonon interactions and demonstrates improved coherent acoustic control of SiV spins.

Findings

Achieved over twofold increase in Rabi frequency for SiV spin control.

Demonstrated effective acoustic control via surface acoustic waves in the integrated platform.

Enabled potential for phonon-based quantum information processing.

Abstract

Negatively charged silicon vacancy (SiV) center in diamonds are leading candidates for solid-state quantum memories that can be controlled using electromagnetic or acoustic waves. The latter are particularly promising due to strong strain response of SiV, enabling large spin-phonon interaction strengths. Indeed, coherent spin control via surface acoustic waves (SAW) has been demonstrated and is essential for developing on-chip phononic quantum networks. However, the absence of piezoelectricity in diamond requires interfacing with a piezoelectric material for efficient transduction and delivery of acoustic waves to spins in diamonds. Here, we demonstrate a heterogeneously integrated phononic platform that combines thin-film lithium niobate (TFLN) with diamond to enable acoustic control of single SiV spins. Additionally, leveraging large SAW-induced strain at the location of SiV, we achieve coherent acoustic control of an electron spin with more than twofold improvement in Rabi frequency compared to the state-of-the-art devices based on aluminum nitride-on-diamond. This work represents a crucial step towards realizing phonon-based quantum information processing systems.