Dr. Amit Finkler
Department of Chemical and Biological Physics, Weizmann Institute of Science, Israel
Investigating spin and charge noise in strongly correlated electron systems is a valuable way to analyze their physical properties and unlock new phases of matter. With the emergence of vdW materials in the last two decades, this has become a significant characterization scheme as the low-dimensionality accentuates the effect of fluctuations.
In this context, nitrogen-vacancy (NV) center-based magnetometry has been proven to be a versatile sensor for various classes of magnetic materials in broad temperature and frequency ranges.
In this seminar, I will show how we use longitudinal relaxation time T1 of single NV centers to investigate the spin dynamics of nanometers-thin flakes of ruthenium trichloride (α-RuCl3), a candidate quantum spin liquid, at room temperature. We observe a significant reduction in the T1 in the presence of α-RuCl3 in proximity to our NVs, which we attribute to paramagnetic spin noise confined in the 2D hexagonal plane. Furthermore, the T1 time exhibits an almost linear increase with an applied external magnetic field. We associate this trend with the alteration of spin and charge noise in α-RuCl3 under an external magnetic field.
While these findings are still a long way from telling us something about the perplexing low-temperature phase of the material, they do suggest that the influence of the room-temperature spin dynamics of α-RuCl3 on the longitudinal relaxation time of the NV center can be used to gain information on the material itself and the technique itself to be used on other 2D materials.