DonorSpins

DonorSpins is a term used in quantum information science to describe spin qubits based on donor atoms embedded in a semiconductor host, most commonly phosphorus donors in silicon. The donor atom provides localized electronic and nuclear spin degrees of freedom that can serve as quantum bits for initialization, manipulation, and readout.

In a DonorSpins system, the qubit can be encoded in the electron spin of the donor, the donor nucleus, or a coupled electron–nuclear system. Hyperfine interactions between electron and nuclear spins enable coherent control and can provide long-lived quantum memory. Coherence times improve with isotopic purification of the host material to reduce magnetic noise and with optimized fabrication methods.

Control methods for DonorSpins include resonant microwave techniques for electron spins and radiofrequency methods for nuclear spins, as well as electrical tuning to adjust exchange interactions between neighboring donors. Readout is commonly achieved through spin-to-charge conversion combined with sensitive charge detectors such as a single-electron transistor or a quantum point contact; optical readout is explored in some donor-host materials.

The DonorSpins concept is closely associated with silicon-based quantum computing architectures, particularly the Kane proposal, which envisions addressable donor nuclear spins with mediated two-qubit gates. Experimental progress has demonstrated individual spin control and basic two-qubit interactions in donor systems, while challenges remain in precise donor placement, scalable integration with classical electronics, and error-correction implementation.

Applications of DonorSpins include scalable quantum processors, quantum memories, and high-sensitivity quantum sensors. The field is active in academic and industry research programs, with ongoing work in materials engineering, device fabrication, and architecture design.