Excitation and coherent control of spin qudit modes in silicon carbide at room temperature.

One of the challenges in the field of quantum sensing and information processing is to selectively address and coherently manipulate highly homogeneous qubits subject to external perturbations. Here, we present room-temperature coherent control of high-dimensional quantum bits, the so-called qudits, associated with vacancy-related spins in silicon carbide enriched with nuclear spin-free isotopes. In addition to the excitation of a spectrally narrow qudit mode at the pump frequency, several other modes are excited in the electron spin resonance spectra whose relative positions depend on the external magnetic field. We develop a theory of multipole spin dynamics and demonstrate selective quantum control of homogeneous spin packets with sub-MHz spectral resolution. Furthermore, we perform two-frequency Ramsey interferometry to demonstrate absolute dc magnetometry, which is immune to thermal noise and strain inhomogeneity.

Optically Addressable Silicon Vacancy-Related Spin Centers in Rhombic Silicon Carbide with High Breakdown Characteristics and ENDOR Evidence of Their Structure.

We discovered a family of uniaxially oriented silicon vacancy-related centers with S=3/2 in a rhombic 15R-SiC crystalline matrix. We demonstrate that these centers exhibit unique characteristics such as optical spin alignment up to the temperatures of 250°C. Thus, the range of robust optically addressable vacancy-related spin centers is extended to the wide class of rhombic SiC polytypes. To use these centers for quantum applications it is essential to know their structure. Using high frequency electron nuclear double resonance, we show that the centers are formed by negatively charged silicon vacancies V_{Si}^{-} in the paramagnetic state with S=3/2 that is noncovalently bonded to the neutral carbon vacancy V_{C}^{0} in the nonparamagnetic state, located on the adjacent site along the SiC symmetry c axis.

Silicon carbide light-emitting diode as a prospective room temperature source for single photons.

Generation of single photons has been demonstrated in several systems. However, none of them satisfies all the conditions, e.g. room temperature functionality, telecom wavelength operation, high efficiency, as required for practical applications. Here, we report the fabrication of light-emitting diodes (LEDs) based on intrinsic defects in silicon carbide (SiC). To fabricate our devices we used a standard semiconductor manufacturing technology in combination with high-energy electron irradiation. The room temperature electroluminescence (EL) of our LEDs reveals two strong emission bands in the visible and near infrared (NIR) spectral ranges, associated with two different intrinsic defects. As these defects can potentially be generated at a low or even single defect level, our approach can be used to realize electrically driven single photon source for quantum telecommunication and information processing.