The Role of Electrolytes in the Relaxation of Near-Surface Spin Defects in Diamond
At a Glance
Section titled āAt a Glanceā| Metadata | Details |
|---|---|
| Publication Date | 2023-05-22 |
| Journal | ACS Nano |
| Authors | Fabian A. Freire-Moschovitis, Roberto Rizzato, Anton Pershin, Moritz R. Schepp, Robin D. Allert |
| Institutions | HUN-REN Wigner Research Centre for Physics, Institute for Solid State Physics and Optics |
| Citations | 22 |
Abstract
Section titled āAbstractāQuantum sensing with spin defects in diamond, such as the nitrogen vacancy (NV) center, enables the detection of various chemical species on the nanoscale. Molecules or ions with unpaired electronic spins are typically probed by their influence on the NV centerās spin relaxation. Whereas it is well-known that paramagnetic ions reduce the NV centerās relaxation time (<i>T</i><sub>1</sub>), here we report on the opposite effect for diamagnetic ions. We demonstrate that millimolar concentrations of aqueous diamagnetic electrolyte solutions increase the <i>T</i><sub>1</sub> time of near-surface NV center ensembles compared to pure water. To elucidate the underlying mechanism of this surprising effect, single and double quantum NV experiments are performed, which indicate a reduction of magnetic and electric noise in the presence of diamagnetic electrolytes. In combination with <i>ab initio</i> simulations, we propose that a change in the interfacial band bending due to the formation of an electric double layer leads to a stabilization of fluctuating charges at the interface of an oxidized diamond. This work not only helps to understand noise sources in quantum systems but could also broaden the application space of quantum sensors toward electrolyte sensing in cell biology, neuroscience, and electrochemistry.