Solid-state spin color centers are of utmost importance for the application of quantum technologies, especially the nitrogen-vacancy (NV) centers in diamond. Since the detection of individual diamond NV centers at room temperature was reported in 1997, the diamond NV centers have been widely applied to versatile fields including quantum computation, quantum networks and quantum sensing.
In recent years, to take advantage of more mature material processing and device integration technologies, researchers have been seeking similar color centers in other semiconductor materials. Among them, the spin color centers in silicon carbide (SiC), including silicon vacancies (missing a silicon atom) and divacancies (missing a silicon atom and an adjacent carbon atom), have attracted interest due to their excellent optical and spin properties.
Although the spin coherent control of the single silicon vacancy in SiC has been realized, the single silicon vacancy in natural bulk SiC has a low spin readout contrasts of 2%, and a low single-photon count rate of 10 kilo counts per second at room temperature, which greatly restricts its application. Moreover, the spin coherent control of the single divacancy color center at room temperature has not been realized.
Recently, the researchers from University of Science and Technology of China realized the spin coherent control of single divacancy color centers in SiC at room temperature with a high readout contrast. To our knowledge, this is the second solid-state color center with both the high spin readout contrast and high photon count rate at room temperature since the discovery of diamond NV centers. This achievement is of great significance for quantum information technology based on the mature SiC semiconductor materials.
Researchers prepared arrays of single divacancy color centers in SiC using the ion implantation technologies [ACS Photonics 6, 1736-1743 (2019); Phys. Rev. Lett. 124, 223601 (2020)]. Furthermore, they realized the spin coherent control of the single divacancy color center at room temperature with the optically detected magnetic resonance (ODMR).
In this work, the authors found that one type of divacancy color centers, namely PL6 color centers, had a high spin readout contrast of 30% and a high single-photon count rate up to 150 kilo counts per second. These two important parameters are an order of magnitude higher than the silicon vacancy color centers in SiC. Moreover, the coherence time of the electron spin at room temperature exceeds to 23 microseconds. The authors further realized the coupling and detection between a single electron spin and an adjacent nuclear spin.
This work lays the foundation for building room-temperature solid-state quantum storage and scalable solid-state quantum networks based on the SiC spin color center system. It is essential for the next generation of hybrid quantum devices to integrate spin defects with a high readout contrast and a high photon count rate into high-performance SiC electron devices.
This research received funding from the Ministry of Science and Technology of China, the National Natural Science Foundation of China, the Chinese Academy of Sciences, China Postdoctoral Science Foundation, the National Research, Development and Innovation Office of Hungary and the Ministry of Innovation and Technology of Hungary.
See the article:
Qiang Li, Jun-Feng Wang, Fei-Fei Yan, et al.
Room temperature coherent manipulation of single-spin qubits in silicon carbide with a high readout contrast
Natl Sci Rev, doi: 10.1093/nsr/nwab122
National Science Review