Two-Qubit Spin Entanglement in Coupled Quantum Dots within Strained Quantum Wells

We investigate spin entanglement in a strained Si/SiGe quantum well hosting two laterally coupled quantum dots separated by ~30 nm. The model incorporates strain-induced band modulation and spin–orbit interactions, with particular emphasis on the interplay between Rashba and Dresselhaus terms. Using a two-electron Hamiltonian framework and evaluating entanglement via Wootters concurrence, we demonstrate that the degree of spin entanglement can be effectively tuned by an external magnetic field and by varying the Ge concentration in the heterostructure. In contrast to conventional GaAs-based systems, our results indicate a pronounced dominance of the Dresselhaus contribution, exceeding the Rashba term by approximately one to two orders of magnitude, consistent with reported behavior in Si/SiGe quantum wells. Furthermore, our result reveals that the operational regime supporting stable two-qubit information exchange remains largely insensitive to inter-dot spacing within the considered range. Our reports highlight the potential of strained silicon platforms for controllable spin-based quantum information processing.