Kavli Affiliate: Giordano Scappucci
| First 5 Authors: Lucas E. A. Stehouwer, Merrit P. Losert, Maia Rigot, Davide Degli Esposti, Sara MartÃ-Sánchez
| Summary:
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 enhance the
valley splitting on average. We grow increasingly thinner quantum wells with
broad interfaces to controllably increase the overlap of the electron wave
function with Ge atoms. In these quantum wells, comprehensive quantum Hall
measurements of two-dimensional electron gases reveal a linear correlation
between valley splitting and disorder. Benchmarked against quantum wells with
sharp interfaces, we demonstrate enhanced valley splitting while maintaining a
low-disorder potential environment. Simulations using the experimental Ge
concentration profiles predict an average valley splitting in quantum dots that
matches the enhancement observed in two-dimensional systems. Our results
motivate the experimental realization of quantum dot spin qubits in these
heterostructures.
| Search Query: ArXiv Query: search_query=au:”Giordano Scappucci”&id_list=&start=0&max_results=3