Thermal spike - A. SORKIN with JA and RAFI KALISH

  1. When an implanted ion slows down a highly disrupted, very hot, region forms inside the diamond crystal. This is called a "thermal spike" It can be viewed as the short term local melting of the implantation affected region and is at least initially amorphous.

  2. Samples were prepared which were periodic in x and y directions with fixed diamond layers at top and bottom. The central part was heated to amorphize it, then cooled. Picture below at left is of 192 atoms, after 5,000 steps. Each step 0.5femtoseconds = 0.0005picosecs. Red fourfold, blue threefold, and green twofold coordinated atoms.

  3. Visualizations: see mpg of the still below left, with initial energy equivalent to 23,000K, or see animated gif of the still below left. If the middle layer was not given sufficient energy it returned to diamond: see mpg of the return when initial energy equivalent to 20,000K.

  4. These simulations were repeated for different lattice sizes and also for samples which were initally amorphous, see gif of the amorphous case, (at right above). An animation of its preparation can be viewed, here .

  5. The manuscript describing these results just appeared in PRB.