(a) Structure of twist grain boundary viewed along [-111] direction. Blue atom: GB; dark red atom: bulk. (b)–(d) Dislocation-junction and dislocation-band distribution on GB plane along [110] direction for θ = 20° (b), 40° (c), and 70.53° (d) (Σ 3). Atoms are colored according to potential energy, as indicated by the color bar.