Design and Optimization of Donor-based Spin Qubits in Silicon
Donor-based spin qubits in silicon are promising candidates for solid-state quantum computation as they have exceptionally long coherence time. Single donor and few-donor quantum dots can be patterned by scanning tunneling microscopy based lithography technique in silicon with atomic precision, making them propitious for building a scalable quantum computer. Compared to single donors, few-donor quantum dots have more nuclear spins and extra quantum confinement, leading to additional degrees of freedom to engineer single and multi-qubit operations, while retaining long coherence times. Combined, they can be utilized to obtain outstanding performance or novel approaches for qubit operation. In this work, approaches for design and optimization of donor-based spin qubits in silicon are proposed based on atomistic simulations, focusing on qubit characterization, manipulation and readout. For few-donor qubits, we put forward a metrology technique to obtain their atomic scale information, needed for single qubit manipulation. Also, a new design is introduced for two-qubit gates to gain flexibility in device fabrication and tuning the exchange coupling, in which theoretical guidance to the realization of two-qubit logic is provided. In addition, an all-electric spin control scheme is proposed, giving rise to a promisingly scalable architecture of a donor-based quantum computer. We also explore the electrical and opto-electric hybrid spin readout under realistic electrostatics and device geometry, providing guidance for optimizing device parameters in experiments.
Rahman, Purdue University.
Electrical engineering|Condensed matter physics|Nanotechnology
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