Fig nbsp xA Schematic illustration of a TiN

The only other possibility is for dimers to descend onto the terrace, and this process is preceded by a transition to an unstable configuration, as shown in Fig. 6(c); the N island corner atom is pulled upward, along < 110 >, above one of the adjacent fourfold-hollow sites along the island edge, at the same time as the N dimer atom descends over the island edge into a position above a neighboring hollow site.