2021/08/24 by N. I. Dumoulin Stuyck, F. A. Mohiyaddin, R. Li +3
Materials Science · Physics and Astronomy · #Chemical and Physical Properties of Materials #Coherence (philosophical gambling strategy) #Coherence time #Dephasing #Magnetic field #Magnetic properties of thin films #Quantum and electron transport phenomena #Quantum computer #Quantum decoherence #Qubit #Spin (aerodynamics) #Spin engineering #cond-mat.mes-hall #quant-ph
paper · pdf · doi:10.1063/5.0059939
5 pages, 4 figures
arxiv created 2021/08/24 · openalex created_date 2021/08/30 · openalex publication_date 2021/08/30 · arxiv updated 2021/09/15 · openalex updated_date 2026/08/05
Using micromagnets to enable electron spin manipulation in silicon qubits has emerged as a very popular method, enabling single-qubit gate fidelities larger than 99.9%. However, these micromagnets also apply stray magnetic field gradients onto the qubits, making the spin states susceptible to electric field noise and limiting their coherence times. We describe here a magnet design that minimizes qubit dephasing, while allowing for fast qubit control and addressability. Specifically, we design and optimize magnet dimensions and positions relative to the quantum dots, minimizing dephasing from magnetic field gradients. The micromagnet-induced dephasing rates with this design are up to three orders of magnitude lower than state-of-the-art implementations, allowing for long coherence times. This design is robust against fabrication errors and can be combined with a wide variety of silicon qubit device geometries, thereby allowing exploration of coherence limiting factors and novel upscaling approaches.