Kinikar, AshutoshAshutoshKinikarLevajac, VukanVukanLevajacMoors, KristofKristofMoorsSimion, GeorgeGeorgeSimionBenito, MónicaMónicaBenitoSorée, BartBartSoréeBenito, MonicaMonicaBenito2026-09-282026-09-2820260021-8979https://imec-publications.be/handle/20.500.12860/60502<jats:p>We present a flexible modeling framework for flopping-mode spin qubits that captures the spatial structure of the double-well confinement and magnetic-field-gradient profile going beyond conventional low-energy descriptions. By using this approach, we simulate electric dipole spin resonance-based single-qubit control and evaluate the frequency and spectral purity of the Rabi oscillations across different parameter regimes. Our analysis reveals a fundamental trade-off between fast electrical driving and clean single-mode Rabi oscillations and demonstrates that the standard two-site low-energy approximation can overestimate the Rabi frequency by up to ∼20% in certain parameter regimes. We also investigate two-qubit control by considering two capacitively coupled flopping-mode qubits and derive the corresponding exchange interaction with an appropriately restricted configuration interaction treatment. Our approach reveals the interplay between the spatial profile of the double-well confinement, magnetic field gradient, and Coulomb interaction, which together govern the effective exchange coupling strength. Our spatially resolved modeling framework enables efficient exploration of double-well confinement parameters and magnetic field gradient profiles, enabling a transparent mapping from spatial device properties to flopping-mode qubit parameters and quality metrics.</jats:p>engJournal article10.1063/5.0343213WOS:001856497000001SINGLE-ELECTRON SPINQUANTUM-DOTCOHERENCEFIDELITY1089-7550