Fig. 4: Atomic configuration and dynamic evolution towards atomically sharp γ/α interface.

a Experimentally measured γ/α interface as that in Fig. 3c. b Enlarged interface image with the simulation template inset illustrating corresponding initial configurations of the machine-learning-driven molecular dynamics (ML-MD) model in panel (c, d) detailed configuration in terms of the O sublattice repetitions in γ-Ga₂O₃ (γ-O) and α-Ga₂O₃ (α-O); Ga atoms are big blue (color-coded based on coordination numbers) and O atoms are small red spheres. The γ-phase, boundary, and α-phase regions are colored in purple, cyan, and green, respectively. e Dynamic evolution of the initially mismatched oxygen (A’ | B) stacking layer [labeled by the black box in panel (d)] at 900 K, top-viewed from α[0001]/γ[111] axis, demonstrating the planar slip displacements relative to the initial positions, as indicated by the blue arrows (note, that displacement magnitudes are scaled by a factor of 3 for clarity). The color-coding of oxygen atoms illustrates local stacking types, such as fcc and hcp. At t = 500 ps, the atomically sharp γ/α interface forms with a perfectly matched oxygen (B = B’) stacking layer in accordance with the ML-MD simulation (side-viewed from α [1\(\bar{1}\)00]/γ[110] axis). See Supplementary Movie 1 for the whole evolution process.