Electric Field Effect on NV Centers in Diamond under High Electric Field

Yuki Doi

Changfeng Weng, Jiaxin Zhao, Mengyuan Cai +5 more

Characterizing electric field noise in diamond is crucial for utilizing nitrogen-vacancy (NV) centers as probes and qubits. However, NV centers under axial magnetic fields are sensitive to magnetic fields and thus are limited in their ability to characterize electric fields directly. In this study, we engineered NV centers exhibiting strong intrinsic effective electric fields through ion implantation into CVD-grown diamond. We selected seven NV centers with splittings in the range of 18–66 MHz as the focus of our research. By virtue of the suppression effect of the strong effective field on the magnetic field, the energy level shift caused by the magnetic field was reduced by two orders of magnitude. Combining spectral decomposition techniques, we extracted the electric noise spectrum in the low-frequency range from the environmental noise. Our results indicate that the near-surface electrical noise of the diamond deviates from the 1/f noise model, and two characteristic correlation times were observed within the measured frequency range (1–10 MHz).

Yuhang Guo, Wei Zhu, Jiaxin Zhao +4 more

Electrically driven emission of nitrogen-vacancy (NV) color centers in diamond has recently emerged as a viable candidate for quantum photonics. However, it is challenging to efficiently excite NV centers by an electric field because of the low density of free carriers in doped diamond. Here, we report efficient electroluminescence of neutrally charged nitrogen-vacancy (NV0) color centers under a high electric field (105 V/cm) and study its Stark effect in a MIM (Metal–Insulator–Metal) diamond device. The MIM device was fabricated by electron beam evaporating molybdenum electrodes and microwave plasma chemical vapor depositing a nitrogen-doped diamond epilayer successively on a single-crystal diamond substrate. We demonstrate the field dependence of the electrically driven emission and extract the NV0 ground state electric field susceptibility of 15.83 ± 0.86 GHzmMV−1 from the Stark effect at 5.5 K. Our findings provide a perspective toward electrically exciting color centers in diamond and help one to understand the inherent features of NV0.

Mari Motojima, Yuta Kainuma, Toshu An +2 more

Lee C. Bassett

For quantum information applications, nitrogen-vacancy (NV) centers in diamond combine many of the advantages of atomic systems (optical access, millisecond spin-coherence times) with the engineering flexibility of solid-state devices. Recent demonstrations of coherent coupling between photons and individual NV-center spins [1,2] provide a route to integrating NV-center qubits within photonic networks and for on-demand generation of entangled single-spin/single-photon pairs. Such applications require the ability to tune the NV-center zero-phonon optical transitions, to compensate for natural sample inhomogeneities which perturb the electronic orbital states. Here we demonstrate the ability to electrically control the orbitals of individual NV centers by applying voltages to micron-scale surface gates [3]. Surprisingly, the local electric field experienced by an NV center is significantly enhanced by a photoinduced space charge resulting from photoionization of deep donor impurities within the diamond, even in high-purity single-crystal material (< 5 ppb nitrogen content). Since the photoinduced electric fields are reproducible as a function of gate voltage and are predominantly directed perpendicular to the diamond surface, we can harness them to obtain three-dimensional control of the local electric field vector with surface gates alone. To demonstrate this technique, we tune the excited-state orbital doublet of a strained NV center to degeneracy, as required for some spin-photon entanglement protocols [2], and then adjust the optical transition frequency, showing that we can tune multiple NV centers to have the same degenerate transition energy. This method should enable the coherent coupling of multiple NV center spins to indistinguishable photons within a scalable photonic network.

E. Anastassakis, S. Iwasa, E. Burstein