Magnetic Spectroscopy of the Silicon Vacancy Center in Diamond

The ongoing research on materials, which show interesting magnetic behaviors at cryogenic temperatures e.g., superconducting materials/monolayers, require locally precise and also sensitive magnetic sensors, which are functional under these conditions.<br/>As they are already known for their high sensitivity and good robust optical properties at room temperature, Nitrogen Vacancy Centers (NV) seem to be a suitable candidate. Nevertheless, performing measurements at cryogenic temperatures also opens the door for the usage of other defects like the Silicon Vacancy center (SiV). Whereby the optical properties of the NV do not improve at these temperatures, the SiV shows excellent optical properties and also an ODMR contrast up to 100% is achievable.<br/>To utilize the SiV for this purpose, the dynamics of the electron spin in an external magnetic field have to be investigated in detail, described by the Zeeman term of the Hamiltonian. Pioneering work was already done by Hepp et. all, but limited to a certain direction to the SiV principal axis. For a complete understanding these dynamics have to be further investigated in detail by determining the g-tensor of the SiV. Here we report on recent progress, using magnetic spectroscopy measurements on the SiV to obtain its g-tensor and probe the applicability as a magnetic sensor. Furthermore, these insights can be transferred to other group IV defects allowing for precise alignment of the magnetic field to the quantum axis, which is required for gate operations with high fidelity.