Thermodynamic model for the structure of the 90 degree partial dislocation in diamond cubic semiconductors.*

Recent studies of the 90 degree partial dislocation in diamond cubic semiconductors indicate that the structure of the core is not homogeneous, but rather is a combination of reconstructions and low energy structural excitations, such as kinks and anti-phase defects. As a result, direct investigation of the macroscopic properties of dislocation core by \textit{ab initio} methods is unfeasible. A model is presented that maps the complicated structure of a dislocation core onto a one-dimensional spin lattice. At each lattice site two spins are present, one to represent the reconstructed bonds, and the other kink structures. The model is sufficiently complex to allow expression of the essential nature of the structural excitations along a dislocation line. This Ising-like model can be investigated within a Monte Carlo framework.