| About this Abstract |
| Meeting |
2025 TMS Annual Meeting & Exhibition
|
| Symposium
|
Thin Films and Coatings: Properties, Processing and Applications
|
| Presentation Title |
Charge Redistribution Around Threading Dislocations in III-Nitride Epilayers |
| Author(s) |
Roman Groger, Jan Fikar |
| On-Site Speaker (Planned) |
Roman Groger |
| Abstract Scope |
III-nitrides are ionic-covalent solids in which the ionic contribution to bonding is properly described only by methods based on quantum mechanics. At the level of empirical potentials, the individual ions are often incorporated by assuming fixed partial or formal ionic charges, although this simplification is physically incorrect around crystal lattice defects. Here, we introduce the first ionic-covalent empirical model for III-nitrides with variable ionic charges that are determined self-consistently with ionic positions using the Streitz-Mintmire electronegativity equalization principle. We demonstrate that the presence of charges leads to correct ground states of GaN and AlN. This model is further used to describe the redistribution of charges around threading dislocations in epitaxially grown GaN and AlN, and correlated with quantitative TEM studies employing electron holography and 4D STEM. These studies may elucidate the mechanism through which threading dislocations nucleate in large-mismatch III-nitride heterostructures. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Thin Films and Interfaces, Electronic Materials, Computational Materials Science & Engineering |