Using topological current theory, studies were made of the inner topological structure of disclinations during the melting of two-dimensional systems. From two-dimensional elasticity theory, it was found that there were topological currents for topological defects. The evolution of disclinations was studied, and the branch conditions for generating, annihilating, crossing, splitting and merging of disclinations were given.

Topological Aspect of Disclinations in Two-Dimensional Crystals. W.K.Qi, T.Zhu, Y.Chen, J.R.Ren: Chinese Physics B, 2009, 18, 1002-8