Coupling conduction-band valleys in SiGe heterostructures via shear strain and Ge concentration oscillations

Abstract

Engineering conduction-band valley couplings is a key challenge for Si-based spin qubits. Recent work has shown that the most reliable method for enhancing valley couplings entails adding Ge concentration oscillations to the quantum well. However, ultrashort oscillation periods are difficult to grow, while long oscillation periods do not provide useful improvements. Here, we show that the main benefits of short-wavelength oscillations can be achieved in long-wavelength structures through a second-order coupling process involving Brillouin-zone folding induced by shear strain. We finally show that such strain can be achieved through common fabrication techniques, making this an exceptionally promising system for scalable quantum computing.

arXiv comment13 pages (5 main text), 5 figures. Published version

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Cited by in corpus (5)

• Mapping of valley-splitting by conveyor-mode spin-coherent electron shuttling
• Theory of Valley Splitting in Si/SiGe Spin-Qubits: Interplay of Strain, Resonances and Random Alloy Disorder
• The effects of alloy disorder on strongly-driven flopping mode qubits in Si/SiGe
• Fabrication, characterization and mechanical loading of Si/SiGe membranes for spin qubit devices
• Exact Multi-Valley Envelope Function Theory of Valley Splitting in Si/SiGe Nanostructures