Surface structures of complex intermetallic compounds: An ab initio DFT study for the (100) surface of o-Al(13)Co(4)
- Author(s)
- Marian Krajci, Juergen Hafner
- Abstract
The formation and the structural and electronic properties of the (100) surface of the complex intermetallic compound Al(13)Co(4) have been investigated using ab initio density functional methods. While the layered crystal structure of the compound suggests that the (100) surface is formed by cleaving the crystal between adjacent flat (F) and puckered (P) layers, a simulated cleavage experiment shows that the P layer splits into two complementary parts to preserve the integrity of very stable clusters forming pentagonal bipyramids (PB's). The stable surface is terminated by an incomplete P layer consisting of the tips of the PB clusters and exposing in the interstices that part of the underlying F layer forming the connection between the PB's. The stability of this strongly corrugated surface is further confirmed by the calculation of the surface energies and of the formation energies of surface vacancies, as well as by a simulated high-temperature annealing. The analysis of the electronic structure shows that the stability of the PB clusters arises primarily from strong, partially covalent vertical Co-Al-Co bonds between the tips of the clusters. Simulated scanning tunneling microscopy (STM) images are provided to permit a comparison with the STM experiments of Addou et al. [Phys. Rev. B 80, 014203 (2009)]. Measured and simulated STM images are in good agreement, possible reasons for the remaining differences in the Al/Co contrast are discussed in detail.
- Organisation(s)
- Computational Materials Physics
- External organisation(s)
- Slovenian Academy of Sciences and Arts
- Journal
- Physical Review B
- Volume
- 84
- No. of pages
- 14
- ISSN
- 1098-0121
- DOI
- https://doi.org/10.1103/PhysRevB.84.115410
- Publication date
- 09-2011
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 103009 Solid state physics, 103015 Condensed matter, 103025 Quantum mechanics, 103036 Theoretical physics
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/7a0fec6d-bf29-4e84-a6c6-9d53601fb95d