Valley splitting depending on the size and location of a silicon quantum dot

Abstract

The valley splitting (VS) of a silicon quantum dot plays an important role for the performance and scalability of silicon spin qubits. In this work we investigate the VS of a SiGe/Si/SiGe heterostructure as a function of the size and location of the silicon quantum dot. We use the effective mass approach to describe a realistic system, which takes into account concentration fluctuations at the Si/SiGe interfaces and also the interface roughness. We predict that the size of the quantum dot is an important parameter for the enhancement of the VS and it can also induce a transition between the disorder-dominated to deterministic-enhanced regimes. Analyzing how the VS changes when we move the quantum dot in a specific direction, we obtain that the size of the quantum dot can be used to reduce the variability of the VS, which is relevant for charge/spin shuttling.

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Cited by in corpus (8)

• Mapping of valley-splitting by conveyor-mode spin-coherent electron shuttling
• Strategies for enhancing spin-shuttling fidelities in Si/SiGe quantum wells with random-alloy disorder
• 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
• Suppressing Si Valley Excitation and Valley-Induced Spin Dephasing for Long-Distance Shuttling
• The effects of alloy disorder on strongly-driven flopping mode qubits in Si/SiGe
• Negative exchange interaction in Si quantum dot arrays via valley-phase induced ${\mathbb{Z}}_2$ gauge field