Low dephasing and robust micromagnet designs for silicon spin qubits

Abstract

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 position relative to the quantum dots, minimizing dephasing from magnetic field gradients. The micromagnet-induced dephasing rates with this design are up to 3-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.

arXiv comment5 pages, 4 figures

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Cited by in corpus (13)

• 12-spin-qubit arrays fabricated on a 300 mm semiconductor manufacturing line
• Modelling semiconductor spin qubits and their charge noise environment for quantum gate fidelity estimation
• Single spin qubit geometric gate in a silicon quantum dot
• Modular nanomagnet design for spin qubits confined in a linear chain
• High-fidelity CNOT gate for spin qubits with asymmetric driving using virtual gates
• Decoherence of electron spin qubit during transfer between two semiconductor quantum dots at low magnetic fields
• Leveraging Off-the-Shelf Silicon Chips for Quantum Computing
• Coherence of a field-gradient-driven singlet-triplet qubit coupled to many-electron spin states in 28Si/SiGe
• Optimal design of nanomagnets for on-chip field gradients
• Pursuing high-fidelity control of spin qubits in natural Si/SiGe quantum dot
• The role of antisymmetric orbitals and electron-electron interactions on the two-particle spin and valley blockade in graphene double quantum dots
• Micromagnet-free operation of electron spin qubits in Si/Si${}_{1-x}$Ge${}_x$ vertical double quantum dots
• Nanoscale stray fields from micromagnets for optimal spin qubit architecture