Long-lived electronic spin qubits in single-walled carbon nanotubes

Spins defined in single-walled carbon nanotubes promise ultra-long spin relaxation times, but qubit implementations require confinement of isolated spins. Here the authors report highly confined long-lived electron spins in chemically functionalized nanotubes and demonstrate their coherent control. Electron spins in solid-state systems offer the promise of spin-based information processing devices. Single-walled carbon nanotubes (SWCNTs), an all-carbon one-dimensional material whose spin-free environment and weak spin-orbit coupling promise long spin coherence times, offer a diverse degree of freedom for extended range of functionality not available to bulk systems. A key requirement limiting spin qubit implementation in SWCNTs is disciplined confinement of isolated spins. Here, we report the creation of highly confined electron spins in SWCNTs via a bottom-up approach. The record long coherence time of 8.2 mu s and spin-lattice relaxation time of 13 ms of these electronic spin qubits allow demonstration of quantum control operation manifested as Rabi oscillation. Investigation of the decoherence mechanism reveals an intrinsic coherence time of tens of milliseconds. These findings evident that combining molecular approaches with inorganic crystalline systems provides a powerful route for reproducible and scalable quantum materials suitable for qubit applications.

Automated summary

Researchers report highly confined and long-lived electron spins in chemically functionalized nanotubes and demonstrate their coherent control. These findings indicate that combining molecular approaches with inorganic crystalline systems provides a powerful route for reproducible and scalable quantum materials suitable for qubit applications.