Theory of domains and dislocations in the charge-density-wave states of2H-TaSe2

Rules are given which govern the formation of domains and dislocations in the charge-density-wave states of $2H$-Ta${\mathrm{Se}}_2$. New dislocations are described, and it is pointed out that three different types of dislocations are found frequently in $2H$-Ta${\mathrm{Se}}_2$. Various processes involving dislocations are described, and a dislocation Burgers vector which is conserved in these processes is defined. An equation of motion for a dislocation is proposed.