Single-spin qubits in isotopically enriched silicon at low magnetic field.

ABSTRACT: Single-electron spin qubits employ magnetic fields on the order of 1 Tesla or above to enable quantum state readout via spin-dependent-tunnelling. This requires demanding microwave engineering for coherent spin resonance control, which limits the prospects for large scale multi-qubit systems. Alternatively, singlet-triplet readout enables high-fidelity spin-state measurements in much lower magnetic fields, without the need for reservoirs. Here, we demonstrate low-field operation of metal-oxide-silicon quantum dot qubits by combining coherent single-spin control with high-fidelity, single-shot, Pauli-spin-blockade-based ST readout. We discover that the qubits decohere faster at low magnetic fields with [Formula: see text]??s and [Formula: see text]??s at 150?mT. Their coherence is limited by spin flips of residual ²⁹Si nuclei in the isotopically enriched ²⁸Si host material, which occur more frequently at lower fields. Our finding indicates that new trade-offs will be required to ensure the frequency stabilization of spin qubits, and highlights the importance of isotopic enrichment of device substrates for the realization of a scalable silicon-based quantum processor.

SUBMITTER: Zhao R 

PROVIDER: S-EPMC6890755 | biostudies-literature | 2019 Dec

REPOSITORIES: biostudies-literature