Interface and electromagnetic effects in the valley splitting of Si quantum dots

Abstract

The performance and scalability of silicon spin qubits depend directly on the value of the conduction band valley splitting. In this work, we investigate the influence of electromagnetic fields and the interface width on the valley splitting of a quantum dot in a Si/SiGe heterostructure. We propose a new three-dimensional theoretical model within the effective mass theory for the calculation of the valley splitting in such heterostructures that takes into account the concentration fluctuation at the interfaces and the lateral confinement. With this model, we predict that the electric field is an important parameter for valley splitting engineering, since it can shift the probability distribution away from small valley splittings for some interface widths. We also obtain a critical softness of the interfaces in the heterostructure, above which the best option for spin qubits is to consider an interface as wide as possible.

References in corpus (6)

• An addressable quantum dot qubit with fault-tolerant control fidelity
• A Reconfigurable Gate Architecture for Si/SiGe Quantum Dots
• Physical mechanisms of interface-mediated intervalley coupling in Si
• Measurement of valley splitting in high-symmetry Si/SiGe quantum dots
• Magnetic field dependence of valley splitting in realistic Si/SiGe quantum wells
• Spin relaxation in a Si quantum dot due to spin-valley mixing

Cited by in corpus (11)

• Strategies for enhancing spin-shuttling fidelities in Si/SiGe quantum wells with random-alloy disorder
• Valley-Free Silicon Fins Caused by Shear Strain
• Valley splitting depending on the size and location of a silicon quantum dot
• Theory of Valley Splitting in Si/SiGe Spin-Qubits: Interplay of Strain, Resonances and Random Alloy Disorder
• Partial Landau-Zener transitions and applications to qubit shuttling
• Scalable Parity Architecture With a Shuttling-Based Spin Qubit Processor
• Fabrication, characterization and mechanical loading of Si/SiGe membranes for spin qubit devices
• The effects of alloy disorder on strongly-driven flopping mode qubits in Si/SiGe
• Omnidirectional shuttling to avoid valley excitations in Si/SiGe quantum wells
• Negative exchange interaction in Si quantum dot arrays via valley-phase induced ${\mathbb{Z}}_2$ gauge field
• Phonon-induced frequency shift in semiconductor spin qubits