A positive spin on SiC defects
Two studies suggest SiC is a promising candidate for atomic-scale spintronics
Two international research teams have published studies that suggest SiC is a promising candidate for atomic-scale spintronics. Both reported their results in Nature Materials.
The elimination of defects from SiC has aided its move to the forefront of optoelectronics and power-electronics. However, certain SiC defects have electronic states with sharp optical and spin transitions, which make them a potential platform for spintronics, quantum information processing, and nanoscale sensing.
Other spintronic contenders such as defects in diamond or individual phosphorus dopants in silicon, either lack an efficient spin/photon interface or established fabrication methods. In contrast, SiC has a large bandgap with deep defects and benefits from mature fabrication techniques.
In one study, researchers from the University of Chicago, the University of California, Linköping University, and the Japan Atomic Energy Agency, show that individual electron spins in high-purity monocrystalline 4H-SiC can be isolated and coherently controlled.
Bound to neutral divacancy defects, these states exhibit exceptionally long ensemble Hahn-echo spin coherence times, exceeding 1ms. "Coherent control of single spins in a material amenable to advanced growth and microfabrication techniques is an exciting route towards wafer-scale quantum technologies," they write.
In the second study, scientists from the University of Stuttgart, Linköping University, Beijing Computational Science Research Center, Japan Atomic Energy Agency, Hungarian Academy of Sciences, and the Budapest University of Technology and Economics, report the characterisation of photoluminescence and optical spin polarisation from single silicon vacancies in SiC.
In their paper, they demonstrate that single spins can be addressed at room temperature. They report finding long spin coherence times under ambient conditions. "Our study provides evidence that SiC is a promising system for atomic-scale spintronics and quantum technology," they conclude.
'Coherent control of single spins in silicon carbide at room temperature' by Matthias Widmann et al, Nature Materials 14, 164-168 (2015) doi:10.1038/nmat4145.
"˜Isolated electron spins in silicon carbide with millisecond coherence times' by David J Christie et al, Nature Materials 14, 160-163 (2015) doi:10.1038/nmat4144
