This dataset contains numerical simulations of bottom-heated, top-heavy double-diffusive convection in a rotating spherical shell. These models are designed to investigate convective dynamics in planetary interiors, with a particular focus on processes occurring near the top of Earth’s outer core [1]. The simulations span a range of thermal and compositional forcings, enabling the study of how lower-mantle heterogeneities influence core convection. The dataset provides: 1. Simulation state files (final states and time-averaged states) in NetCDF format. Due to the large size of full state outputs, only these two files are included. 2. Time-series outputs of key dynamical variables. 3. Post-processed diagnostic quantities, including spatial and temporal averages, kinetic energy budgets, forces relevant to double-diffusive dynamics [2]. 4. Diagnostic quantities to assess possible thermally and/or compositionally stratified layers near the core–mantle boundary. All simulations were produced using the Leeds Spherical Dynamo Code [3] and run on the ARCHER2 high-performance computing system. References: [1] https://doi.org/10.48550/arXiv.2507.03538 [2] https://doi.org/10.1017/jfm.2025.259 [3] https://github.com/Leeds-Spherical-Dynamo/leeds-spherical-dynamo