Hybrid nanophotonic-nanomagnonic SiC-YiG quantum sensor: I/theoretical design and properties

Jérôme Tribollet

doi:10.1051/epjap/2020200062

Abstract

Here I present the theory of a new hybrid paramagnetic-ferrimagnetic SiC-YiG quantum sensor. It is designed to allow sub-nanoscale single external spin sensitivity optically detected pulsed electron electron double resonance spectroscopy, using an X band pulsed EPR spectrometer and an optical fiber. The sensor contains one single V2 negatively charged silicon vacancy color center in 4H-SiC, whose photoluminescence is waveguided by a 4H-SiC nanophotonic structure towards an optical fiber. This V2 spin probe is created by ion implantation at a depth of few nanometers below the surface, determined by optically detected paramagnetic resonance under the strong magnetic field gradient of a YiG ferrimagnetic nanostripe located on the back-side of the nanophotonic structure. This gradient also allow the study, slice by slice at nanoscale, of the target paramagnetic sample. The fabrication process of this quantum sensor, its magnetic and optical properties, its external spins sensing properties in a structural biology context, and its integration to a standard commercially available pulsed EPR spectrometer are all presented here.

Highlights

Electron paramagnetic resonance [1] (EPR) investigation of electron spins localized inside, at surfaces, or at interfaces of ultrathin films is highly relevant to many fields [2,3,4,5,6]
The sensor contains one single V2 negatively charged silicon vacancy color center in 4H-SiC, whose photoluminescence is waveguided by a 4H-SiC nanophotonic structure towards an optical fiber. This V2 spin probe is created by ion implantation at a depth of few nanometers below the surface, determined by optically detected paramagnetic resonance under the strong magnetic field gradient of a YiG ferrimagnetic nanostripe located on the back-side of the nanophotonic structure
The quantum sensor proposed here contains a YIG nanostripe, as already said above, whose design should allow to perform Optically Detected paraMagnetic Resonance (ODMR) test of the sub surface V2 spin probe under a strong dipolar magnetic field gradient, as well as ODPELDOR under this strong dipolar magnetic field gradient to improve the spatial resolution of ODPELDOR down to nanoscale

Summary

Introduction

Electron paramagnetic resonance [1] (EPR) investigation of electron spins localized inside, at surfaces, or at interfaces of ultrathin films is highly relevant to many fields [2,3,4,5,6]. In the fields of photovoltaic [7] and photochemistry [8], EPR is useful to study the spins of photo-created electron-hole pairs, their dissociation, and their eventual transport or chemical reaction occurring at some relevant interface. In the context of the development of new theranostic agents for nanomedicine, it is relevant to study ligandprotein molecular recognition events occurring on surfaces by EPR, using for example, bifunctional spin labels [13]. Commercial EPR spectrometers have generally not enough sensitivity [14] for studying those thin films when target spins are diluted, and, for sure, they cannot detect a single external spin. While home-made EPR experimental setups have been developed recently allowing to reach the single spin sensitivity, by optically [15,16,17,18,19,20] (ODMR), electrically [21] or mechanically [22] detected EPR, a powerfull upgrade strategy allowing to reach both the sub-nanoscale resolution and the single external spin sensitivity, while still using a commercially available pulsed EPR X band spectrometer, is clearly lacking and is highly relevant for most EPR users worldwide

Methods

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Discussion

Conclusion