Figure 3. Traces of the trajectories of D and O ions.

The traces of the trajectories are accumulated over 8 ps in the P2₁/c-SI at 1,400 K and 1.9 TPa. The red and grey regions are traces of the trajectories of each individual O and D ions, respectively. The green dash lines indicate the ‘sausage'-like high density regions of D. The solid black line indicates the unit cell of P2₁/c-SI. The O ions oscillate around the equilibrium positions, while the D ions are fully diffusive. (a) Projection along [201] of the P2₁/c-SI unit cell. (b) Projection along [010] of the P2₁/c-SI unit cell. (c) Projection along [201] × [010] of the P2₁/c-SI unit cell. The blue regions are traces of the trajectories of D ions at 400 K and 1.9 TPa, when the system is in the crystalline regime. The different distribution of blue and grey traces indicates strong anharmonicity.