In Situ Studies of Stress Environment in Amorphous Solids Using Negatively Charged Nitrogen Vacancy (NV^–) Centers in Nanodiamond

Abstract

Amorphous solids, which show characteristic differences from crystals, are common in daily usage. Glasses, gels, and polymers are familiar examples, and polymers are particularly important in terms of their role in construction and crafting. Previous studies have mainly focused on the bulk properties of polymeric products, and the local properties are less discussed. Here, we designed a distinctive protocol using the negatively charged nitrogen vacancy (NV − ) center in nanodiamond to study properties inside polymeric products in situ. Choosing the curing of poly(dimethylsiloxane) (PDMS) and the polymerization of cyanoacrylate as subjects of investigation, we measured the time dependence of local pressure and strain in the materials during the chemical processes. From the measurements, we were able to probe the local shear stress inside the two polymeric substances in situ. By regarding the surprisingly large shear stress as the internal tension, we attempted to provide a microscopic explanation for the ultimate tensile strength (UTS) of a bulk solid. Our current methodology is applicable to any kind of transparent amorphous solids with the stress in the order of MPa and to the study of in situ properties in nanoscale. With better apparatus, we expect the limit can be pushed to sub-MPa scale.

NV microscopy of thermally controlled stresses caused by Cr$_2$O$_3$ thin films

“…Measuring of stresses under the antenna and under uncoated surface could reveal a stressfree temperature. Similar principles might apply to reflective coatings that are used for some applications, and other cases of material deposition on the surface of the diamond [54] as well as gluing diamond crystals to different surfaces [23,55].…”

“…Fortu-nately for NV-based applications, the NV center itself could be used for quantitative characterization of local stresses [18,19], providing an intrinsic and accurate sensing, whatever we want to mitigate or exploit the strains. Ensembles of NV centers, in turn, can be used for mapping of stresses in a shallow NV layer [20][21][22][23][24]. The latest study demonstrates high sensitivity ac magnetometry for three-dimensional strain mapping with micron-scale spatial resolution with two order-of-magnitude improvement in volume-normalized sensitivity [25].…”

Diamond quantum sensors: from physics to applications on condensed matter research

“…Hence, the stress tensor of a mechanical system can be fully reconstructed via NV sensing. By carefully analysing the ODMR spectrum, the stress tensor can be computed and gives detailed information on the mechanical system [11,[46][47][48][49]. In addition, the NV centre is robust under pressure.…”

High-precision mapping of diamond crystal strain using quantum interferometry

“…1a.) Previous diamond strain measurements using NV centers [1,20,21,29,30] were performed via continuous wave optically detected magnetic resonance (CW-ODMR) -a simple, robust technique where laser and MW fields are continuously applied to the diamond and the MW frequency is swept or modulated. When the MW drive is resonant with the |0 → |±1 spin transitions, the output NV fluorescence decreases as population transfers between spin states.…”

“…Strain-mediated couplings also underlie hybrid quantum-nanomechanical systems [27,28]. Small diamonds as in situ strain sensors can be widely deployed as in high-pressure diamond anvil cells or in curing amorphous solids [29,30]. Finally, sensitive measurements of damage-induced strain in diamond are essential to proposed diamond-based particle detectors, such as for directional detection of dark matter consisting of weakly interacting massive particles (WIMPs) [31,32].…”