Fig. 8: Reinforcement learning and nudged elastic band determined N2 diffusion pathway and reaction barriers on Fe(111) surface.

The identified N2 diffusion path on the bare Fe(111) surface from the one top site to another top site as determined by reinforcement learning (RL) (a), followed by the nudged elastic band (NEB) calculation (b) to determine the reaction barriers and transition state. The Fe atoms in the top, sublayer, deep-layer, and 4th–6th layers are represented by light blue, orange, purple, and bronze spheres, respectively. The N atom is represented by the blue sphere. In panel a, the black arrow indicates the direction of N2 diffusion. In panel b, the blue squares represent the calculated energetics along the NEB reaction path, while the dashed line represents the corresponding fitting curve. Source data for b are provided as a Source Data file. The structure files are provided in Supplementary Data 1.