The silicon vacancy in silicon carbide is a strong emergent candidate for applications in quantum information processing and sensing. We perform room temperature optically-detected magnetic resonance and spin echo measurements on an ensemble of vacancies and find the properties depend strongly on magnetic field. The spin echo decay time varies from less than 10 $mu$s at low fields to 80 $mu$s at 68 mT, and a strong field-dependent spin echo modulation is also observed. The modulation is attributed to the interaction with nuclear spins and is well-described by a theoretical model.
The silicon monovacancy in 4H-SiC is a promising candidate for solid-state quantum information processing. We perform high-resolution optical spectroscopy on single V2 defects at cryogenic temperatures. We find favorable low temperature optical properties that are essential for optical readout and coherent control of its spin and for the development of a spin-photon interface. The common features among individual defects include two narrow, nearly lifetime-limited optical transitions that correspond to $m_s{=}pm 3/2$ and $m_s{=}pm 1/2$ spin states with no discernable zero-field splitting fluctuations. Initialization and readout of the spin states is characterized by time-resolved optical spectroscopy under resonant excitation of these transitions, showing significant differences between the $pm 3/2$ and $pm 1/2$ spin states. These results are well-described by a theoretical model that strengthens our understanding of the quantum properties of this defect.
Solid-state color centers with manipulatable spin qubits and telecom-ranged fluorescence are ideal platforms for quantum communications and distributed quantum computations. In this work, we coherently control the nitrogen-vacancy (NV) center spins in silicon carbide at room temperature, in which telecom-wavelength emission is detected. We increase the NV concentration six-fold through optimization of implantation conditions. Hence, coherent control of NV center spins is achieved at room temperature and the coherence time T2 can be reached to around 17.1 {mu}s. Furthermore, investigation of fluorescence properties of single NV centers shows that they are room temperature photostable single photon sources at telecom range. Taking advantages of technologically mature materials, the experiment demonstrates that the NV centers in silicon carbide are promising platforms for large-scale integrated quantum photonics and long-distance quantum networks.
We report on acoustically driven spin resonances in atomic-scale centers in silicon carbide at room temperature. Specifically, we use a surface acoustic wave cavity to selectively address spin transitions with magnetic quantum number differences of $pm$1 and $pm$2 in the absence of external microwave electromagnetic fields. These spin-acoustic resonances reveal a non-trivial dependence on the static magnetic field orientation, which is attributed to the intrinsic symmetry of the acoustic fields combined with the peculiar properties of a half-integer spin system. We develop a microscopic model of the spin-acoustic interaction, which describes our experimental data without fitting parameters. Furthermore, we predict that traveling surface waves lead to a chiral spin-acoustic resonance, which changes upon magnetic field inversion. These results establish silicon carbide as a highly-promising hybrid platform for on-chip spin-optomechanical quantum control enabling engineered interactions at room temperature.
Silicon vacancies in silicon carbide have been proposed as an alternative to nitrogen vacancy centers in diamonds for spintronics and quantum technologies. An important precondition for these applications is the initialization of the qubits into a specific quantum state. In this work, we study the optical alignment of the spin 3/2 negatively charged silicon vacancy in 6H-SiC. Using a time-resolved optically detected magnetic resonance technique, we coherently control the silicon vacancy spin ensemble and measure Rabi frequencies and spin-lattice relaxation time of all three transitions. Then to study the optical initialization process of the silicon vacancy spin ensemble, the vacancy spin ensemble is prepared in different ground states and optically excited. We describe a simple rate equation model that can explain the observed behaviour and determine the relevant rate constants.
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.
S. G. Carter
,O. O. Soykal
,Pratibha Dev
.
(2015)
.
"Spin Coherence and Echo Modulation of the Silicon Vacancy in 4H-SiC at Room Temperature"
.
Sam Carter
هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا