Researchers at the Department of Physics, Chalmers University of Technology published a paper in the American Chemical Society on the low-temperature phase of formamidinium lead iodide (FAPbI3). The research examined its structural behavior and cation dynamics, providing insights relevant to solar cell applications. It used a machine-learned potential with molecular dynamics simulations to investigate crystal structure, octahedral tilting, and formamidinium cation arrangements. The results showed the octahedral tilt pattern and described rotational dynamics where the cations became frozen in a metastable state instead of reaching the thermodynamic ground state. Comparisons with nuclear magnetic resonance and inelastic neutron scattering spectra showed good agreement, aligning the simulations with experimental data. The work provided insights into structural behavior and explained experimental challenges in identifying the true ground state.