Piezoelectric polarization associated with dislocations in wurtzite GaN

The piezoelectric polarization and its associated charge density are calcul ated for edge, screw, and mixed dislocations oriented parallel to the c axi s in wurtzite GaN. It is shown that the polarization field generated by scr ew components of dislocations is divergence free, and thus does not generat e electric fields. Edge dislocations produce polarization fields that have nonzero divergence only at interfaces. These characteristics minimize the e lectrical and optical effects of the dislocations mediated by the piezoelec tric effect. (C) 1999 American Institute of Physics. [S0003-6951(99)05304-8 ].