We report the experimental study of the temperature-dependence of the longitudinal spin relaxation time $T_1$ of single Nitrogen-Vacancy (NV) centers hosted in nanodiamonds. To determine the relaxation mechanisms at stake, measurements of the $T_1$ relaxation time are performed for a set of individual NV centers both at room and cryogenic temperatures. The results are consistant with a temperature-dependent relaxation process which is attributed to a thermally-activated magnetic noise produced by paramagnetic impurities lying on the nanodiamond surface. These results confirm the existence of surface-induced spin relaxation processes occurring in nanodiamonds, which are relevant for future developments of sensitive nanoscale NV-based quantum sensors.
We investigate the magnetic field dependent photo-physics of individual Nitrogen-Vacancy (NV) color centers in diamond under cryogenic conditions. At distinct magnetic fields, we observe significant reductions in the NV photoluminescence rate, which indicate a marked decrease in the optical readout efficiency of the NVs ground state spin. We assign these dips to excited state level anti-crossings, which occur at magnetic fields that strongly depend on the effective, local strain environment of the NV center. Our results offer new insights into the structure of the NVs excited states and a new tool for their effective characterization. Using this tool, we observe strong indications for strain-dependent variations of the NVs orbital g-factor, obtain new insights into NV charge state dynamics, and draw important conclusions regarding the applicability of NV centers for low-temperature quantum sensing.
We demonstrate electrical detection of the $^{14}$N nuclear spin coherence of NV centers at room temperature. Nuclear spins are candidates for quantum memories in quantum-information devices and quantum sensors, and hence the electrical detection of nuclear spin coherence is essential to develop and integrate such quantum devices. In the present study, we used a pulsed electrically detected electron-nuclear double resonance technique to measure the Rabi oscillations and coherence time ($T_2$) of $^{14}$N nuclear spins in NV centers at room temperature. We observed $T_2 approx$ 0.9 ms at room temperature. Our results will pave the way for the development of novel electron- and nuclear-spin-based diamond quantum devices.
Using pulsed photoionization the coherent spin manipulation and echo formation of ensembles of NV- centers in diamond are detected electrically realizing contrasts of up to 17 %. The underlying spin-dependent ionization dynamics are investigated experimentally and compared to Monte-Carlo simulations. This allows the identification of the conditions optimizing contrast and sensitivity which compare favorably with respect to optical detection.
We report on sensing stability of nanodiamond (ND) quantum sensors in various pH aqueous buffer solutions for the two detection schemes of quantum decoherence spectroscopy and thermometry. The electron spin properties of single nitrogen-vacancy (NV) centers in 25-nm-sized NDs have been characterized by a spin-measurement compatible perfusion (SMCP) chamber where observing the same individual NDs in different buffer solutions is possible. With this system, we have determined the stability of the NV quantum sensors during the pH change from 4 to 11 as the fluctuations of +- 12% and +- 0.2 MHz for the spin coherence time ($T_2$) and the resonance frequency ($omega_0$) of their mean values, which are comparable to the instrumental error of the measurement system. Here, we discuss the importance of characterizing the sensing stability during pH changes and how the present observations affect ND-based NV quantum sensing.
The temperature-dependent electron spin relaxation of positively charged excitons in a single InAs quantum dot (QD) was measured by time-resolved photoluminescence spectroscopy at zero applied magnetic fields. The experimental results show that the electron-spin relaxation is clearly divided into two different temperature regimes: (i) T < 50 K, spin relaxation depends on the dynamical nuclear spin polarization (DNSP) and is approximately temperature-independent, as predicted by Merkulov et al. (ii) T > about 50 K, spin relaxation speeds up with increasing temperature. A model of two LO phonon scattering process coupled with hyperfine interaction is proposed to account for the accelerated electron spin relaxation at higher temperatures.
Timothee de Guillebon
,Baptiste Vindolet
,Jean-Franc{c}ois Roch
.
(2020)
.
"Temperature-dependence of T1 spin relaxation of single NV centers in nanodiamonds"
.
Lo\\\"ic Rondin
هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا