Engineering Ge Profiles in Si/SiGe Heterostructures for Increased Valley Splitting.

ABSTRACT: Electron-spin qubits in Si/SiGe quantum wells are limited by the small and variable energy separation of the conduction-band valleys. While sharp quantum-well interfaces are pursued to increase the valley-splitting energy deterministically, here we explore an alternative approach to enhancing the valley splitting on average. We grow increasingly thinner quantum wells with broad interfaces to controllably increase the electron wave function overlap with Ge atoms. Quantum Hall measurements of two-dimensional electron gases reveal a linear correlation between valley splitting and disorder-induced single-particle energy-level broadening, driven by increasing alloy scattering at the Si/SiGe interface. We demonstrate enhanced valley splitting while maintaining respectable electron mobility, indi

SUBMITTER: Stehouwer LEA 

PROVIDER: S-EPMC12395482 | biostudies-literature | 2025 Aug

REPOSITORIES: biostudies-literature