Abstract
Based on first-principles density functional calculations we propose a novel Al vacancy induced ferromagnetism occurring at the surface of bilayers. Magnetism at cation vacancies away from the surface is quenched due to charge compensation. Magnetic surface Al vacancies are stabilized due to the built-in electric field inside the region that raises the energy of the defect level, making charge compensation unfavorable. Surface Al vacancies prefer to form clusters and exhibit two-dimensional ferromagnetic alignment mediated by a long-range magnetic interaction. These results are discussed in light of recent experimental observations.
- Received 8 December 2013
DOI:https://doi.org/10.1103/PhysRevLett.113.186401
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