Electronic Properties and Metrology Applications of the DiamondNV−Center under Pressure

Abstract

The negatively charged nitrogen-vacancy (NV-) center in diamond has realized new frontiers in quantum technology. Here, the optical and spin resonances of the NV- center are observed under hydrostatic pressures up to 60 GPa. Our results motivate powerful new techniques to measure pressure and image high-pressure magnetic and electric phenomena. Additionally, molecular orbital analysis and semiclassical calculations provide insight into the effects of compression on the electronic orbitals of the NV- center.

Hybrid sensors based on colour centres in diamond and piezoactive layers

“…This allows for the detection of changes in the stray magnetic field [3,[13][14][15][16][17] generated by the piezomagnetic material due to an external stress. We find that the effect of pressure on the NV-center spin can be enhanced by three orders of magnitude when compared to the effect of the direct application of stress on the diamond [8]. However, as the NV center lies close to the magnetic material, the magnetic noise is also expected to become more significant and deteriorate the measurement sensitivity.…”

“…By solving the Langevin equation using the stochastic Heun scheme [34], we calculate the effective stray magnetic field acting on the NV center, and observe a prominent resonance frequency shift in the ODMR spectra, see Fig.2, the shift of ∆ = ω +1 − ω −1 is approximately linear with the stress, and the gradient is about d∆/dσ ∼ 17MHz/MPa for d = 15 nm, which is about three orders of magnitude larger than the shift of the zero-field splitting parameter D under a direct pressure [8]. The enhancement would be more significant for shallower NV, e.g.…”

“…The effect of pressure acting on a diamond lattice for example leads to the coupling between the orbital and spin dynamics of the NV center. This offers a method to measure very high pressure with a sensitivity better than existing techniques [8]. At room temperature, however, the coupling between the strain of diamond lattice and the ground state manifold of the NV-center spin is not sufficient for measuring a low pressure or force.…”

“…The effect of strain on the NV center, as quantified by E, induces ground state spin sub-level mixing and is usually much smaller (on the order of MHz) than the energy splitting along the NV axis. The zero-field splitting D is slightly affected by the stress due to pressure σ, with a gradient of about dD(σ)/dσ ∼ 15kHz/MPa at room temperature [8]. In this work, we will be mostly interested in the case of a weak (sub MPa) pressure, and therefore such a direct effect of stress in the diamond lattice on the NV spin is negligible.…”

All-Optical Thermometry and Thermal Properties of the Optically Detected Spin Resonances of the NV– Center in Nanodiamond

“…Given the observed 3 E ODMR linewidths, this shift indicates a projected pressure sensitivity of ∼ 8(1) MPa Hz −1/2 , which is comparable to the ∼ 0.6 MPa Hz −1/2 sensitivity of the ground state ODMR. 13 The absence of contributions of electron-phonon interactions is theoretically interesting and also explains why the relative shift of D e.s. is much smaller than D g.s.…”