The atomic- and electronic-level structures of a dislocation loop and a stacking fault in 4H-SiC crystal were investigated by using large-scale tight-binding molecular-dynamics simulation. A linear-scaling tight-binding method implemented on a parallel computer was used to accelerate the 9600-atom calculations which were required for such a nanoscale simulation. It wss found that the initial configuration that involved unstable C-C networks around the dislocation loop was relaxed to a structure having six-membered rings, and that the distribution of electron populations was inhomogeneous on the loop. The local electronic density of states showed two peaks in the bulk band gap, where one of these peaks may correspond to the defect state observed in EBIC and cathodoluminescence experiments.

Structures and Local Electronic States of Dislocation Loop in 4H-SiC via a Linear-Scaling Tight-Binding Study. F.Hamasaki, K.Tsuruta: Materials Transactions, 2011, 52[4], 672-6