Ultra-long coherence times amongst room-temperature solid-state spins

• Published in: Nature communications Vol. 10; no. 1; pp. 3766 - 6
• Main Authors: Herbschleb, E. D., Kato, H., Maruyama, Y., Danjo, T., Makino, T., Yamasaki, S., Ohki, I., Hayashi, K., Morishita, H., Fujiwara, M., Mizuochi, N.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 28.08.2019; Nature Publishing Group; Nature Portfolio
• Subjects: 639/301/1005/1009; 639/766/483/2802; 639/925/927/481; 639/925/927/511; Data processing; Diamonds; Electron spin; Electrons; Humanities and Social Sciences; Information processing; Isotopes; multidisciplinary; Phosphorus; Room temperature; Science; Science (multidisciplinary); Single crystals; Single electrons; Solid state
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-019-11776-8

Solid-state single spins are promising resources for quantum sensing, quantum-information processing and quantum networks, because they are compatible with scalable quantum-device engineering. However, the extension of their coherence times proves challenging. Although enrichment of the spin-zero 12 C and 28 Si isotopes drastically reduces spin-bath decoherence in diamond and silicon, the solid-state environment provides deleterious interactions between the electron spin and the remaining spins of its surrounding. Here we demonstrate, contrary to widespread belief, that an impurity-doped (phosphorus) n-type single-crystal diamond realises remarkably long spin-coherence times. Single electron spins show the longest inhomogeneous spin-dephasing time ( T 2 * ≈ 1.5  ms) and Hahn-echo spin-coherence time ( T 2  ≈ 2.4 ms) ever observed in room-temperature solid-state systems, leading to the best sensitivities. The extension of coherence times in diamond semiconductor may allow for new applications in quantum technology. The coherence times of nitrogen-vacancy centres are key factors influencing their performance in quantum applications. Here the authors show that synthesising phosphorus-doped diamond yields nitrogen-vacancy centres with significantly improved T 2 * and T 2 .