Room temperature coherent spin alignment of silicon vacancies in 4H- and 6H-SiC

We report the realization of the optically induced inverse population of the ground-state spin sublevels of the silicon vacancies ($V_{\mathrm{Si}}$) in silicon carbide (SiC) at room temperature. The data show that the probed silicon vacancy spin ensemble can be prepared in a coherent superposition of the spin states. Rabi nutations persist for more than 80 $\mu$s. Two opposite schemes of the optical alignment of the populations between the ground-state spin sublevels of the silicon vacancy upon illumination with unpolarized light are realized in 4H- and 6H-SiC at room temperature. These altogether make the silicon vacancy in SiC a very favorable defect for spintronics, quantum information processing, and magnetometry.Comment: 4 pages, 3 picture

Silicon vacancy in SiC as a promising quantum system for single-defect and single-photon spectroscopy

Results of experiments are presented that suggest that the Si vacancy in SiC is a promising quantum system for single-defect and single-photon spectroscopy in the infrared region. The investigation was carried out with electron paramagnetic resonance (EPR), zero-field optically detected magnetic resonance (ODMR), direct-detection EPR (DD-EPR), and high-resolution fluorescence-excitation spectroscopy. Depending on the temperature, crystal polytype, and crystal position, two opposite schemes have been observed for the optical alignment of the populations of the spin sublevels of the high-spin ground state of the Si vacancy in SiC upon irradiation with unpolarized light at the zero-phonon lines (ZPLs). A giant change has been found in the luminescence intensity of the ZPLs in zero magnetic field upon the application of resonant microwaves which induce transitions between the spin sublevels of the vacancy ground state thus opening the possibility for magnetic-resonance detection of a single vacancy. The optical alignment of the populations of the spin sublevels in the ground state of the Si vacancy was shown with DD-EPR. Surprisingly narrow ZPLs of Si vacancies with a width less than 0.05 meV have been observed which seem to be the narrowest detected so far in SiC. © 2011 American Physical Society

Electron paramagnetic resonance detection of the giant concentration of nitrogen vacancy defects in sintered detonation nanodiamonds

A giant concentration of nitrogen vacancy defects has been revealed by the electron paramagnetic resonance (EPR) method in a detonation nanodiamond sintered at high pressure and temperature. A high coherence of the electron spins at room temperature has been observed and the angular dependences of the EPR spectra indicate the complete orientation of the diamond system. © 2010 Pleiades Publishing, Ltd

Nitrogen centers in nanodiamonds: EPR studies

Electron paramagnetic resonance (EPR) and electron spin echo (ESE) at X-band (9.4 GHz) and W-band (94 GHz) have been used to study defects in natural diamond nanocrystals, detonation nanodiamond (ND) with a size of ∼ 4.5 nm and detonation ND after high-pressure hightemperature (HTHP) sintering with a size of ∼ 8.5 nm. Based on identification of atomic nitrogen centers N0 and nitrogen pairs N2 + detected by means of the high frequency EPR and ESE in natural diamond nanocrystals, atomic nitrogen centers N0 have been discovered in nanodiamond core in detonation ND and detonation ND after sintering. In addition EPR signal of multi-vacancy centers with spin 3/2 seems to be observed in diamond core of detonation ND. © (2010) Trans Tech Publications

Electron spin resonance detection and identification of nitrogen centers in nanodiamonds

Individual nitrogen centers N0 and nitrogen pairs N 2 + have been detected and identified in natural diamond nanocrystals by means of the high-frequency electron spin resonance method. The N0 nitrogen centers have been observed in synthetic diamond nanocrystallites with a size of less than 10 nm produced by high-temperature high-pressure sintering of detonation nanodiamonds. Thus, the possibility of the stable state of impurity nitrogen atoms in diamond nanoparticles has been demonstrated. © 2009 Pleiades Publishing, Ltd

Room Temperature High-Field Spin Dynamics of NV Defects in Sintered Diamonds

Sintered oriented nanodiamond arrays with the extremely high concentrations of the nitrogen-vacancy (NV) centers (up to 103 ppm) were investigated by the W-band (94 GHz) electron spin echo electron paramagnetic resonance techniques. The NV centers were fabricated by the high-pressure high-temperature sintering of detonation nanodiamonds (DND) without the post or prior irradiation of the samples. The processes of polarization and recovery of the equilibrium population of the spin sublevels by optical and microwave pulses have been examined at room temperature in high magnetic fields corresponding to the fine-structure transitions for the NV defects at 94 GHz (3,250-3,450 mT). A long spin coherence time of 1.6 μs and spin-lattice relaxation time of 1.7 ms were measured. The results were compared with those obtained on the NV centers fabricated by the irradiation and subsequent annealing of the commercially available bulk diamonds. It was shown that the relaxation characteristics of the NV defects were similar in the both types of the samples despite the extremely high concentrations of NV defects and isolated nitrogen donors in the sintered DND. © 2013 Springer-Verlag Wien

Detection and identification of nitrogen defects in nanodiamond as studied by EPR

Electron paramagnetic resonance (EPR) and electron spin echo (ESE) at X-band and at high-frequency W-band (95 GHz) have been used to study defects in natural diamond nanocrystals, detonation nanodiamond (ND) with a size of ∼4.5 nm and detonation ND after high-temperature, high-pressure sintering with a size of ∼8.5 nm. Atomic nitrogen centers N0 and nitrogen pairs N2 + have been detected and identified and their structure has been unambiguously determined by means of the high frequency EPR and ESE in natural diamond nanocrystals. In detonation ND and detonation ND after sintering atomic nitrogen centers N0 have been discovered in nanodiamond core. In addition EPR signal of multi-vacancy centers with spin 3/2 seems to be observed in diamond core of detonation ND. © 2009 Elsevier B.V. All rights reserved

Detection and identification of nitrogen centers in nanodiamond: EPR studies

Electron paramagnetic resonance (EPR) and electron spin echo (ESE) at X-band and at high-frequency W-band (95 GHz) have been used to study natural diamond nanocrystals, detonation nanodiamond (ND) with a size of ∼ 4.5 nm and detonation ND after high-temperature, high-pressure sintering with a size of ∼ 8.5 nm. Isolated nitrogen centers N 0 and nitrogen pairs N2+ have been detected and identified, and their structure has been unambiguously determined by means of the high frequency EPR and ESE in natural diamond nanocrystals. In detonation ND and detonation ND after sintering, isolated nitrogen centers N 0 have been discovered in nanodiamond core. In addition EPR signals of multivacancy centers with spin 3/2 seem to be observed in nanodiamond core of detonation ND. Copyright © Taylor & Francis Group, LLC