An L-band emitter with quantum memory in silicon

Abstract Fluorescent centres in silicon have recently attracted great interest, owing to their remarkable properties for quantum technology. Here, we demonstrate that the C-centre in silicon can realise an optically readable quantum register in the L-band wavelength region where the transmission losses in commercial optical fibres are minimal. Our in-depth theoretical characterisation confirms the assignment of the C-centre to the carbon-oxygen interstitial pair defect. We further explore its magneto-optical properties, such as hyperfine and spin-orbit coupling constants from first principles calculations, which are crucial for tight control of the quantum states of the triplet electron spin. Based on this data, we set up quantum optics protocols to initialise and read out the quantum states of the electron spin, and realise a quantum memory by transferring quantum information from the electron spin to proximate 29Si nuclear spins. Our findings establish an optically readable long-living quantum memory in silicon where the scalability of qubits may be achieved by CMOS-compatible technology