Strain induced deep electronic states around threading dislocations in GaN

• Published in: Physical review letters Vol. 93; no. 19; p. 196401
• Main Authors: Lymperakis, L, Neugebauer, J, Albrecht, M, Remmele, T, Strunk, H P
• Format: Journal Article
• Language: English
• Published: United States 05.11.2004
• ISSN: 0031-9007
• DOI: 10.1103/physrevlett.93.196401

Combining through-focus high-resolution transmission electron microscopy and hierarchical multiscale simulations consisting of density-functional theory, analytical empirical potentials, and continuum elastic theory we demonstrate the existence of a new dislocation type in GaN. In contrast with all previously identified or suggested dislocation structures in GaN, all core atoms are fully coordinated; i.e., no broken bonds occur, implying that the dislocation should be electrically inactive. However, as we show, the giant local strain-field around the dislocation core, in combination with the small lattice constant of GaN, causes deep defect states and thus electrically active edge dislocations independent on the specific core structure.