Year: 2010
Type: article
Abstract: By carefully choosing parameters and including more semi-core orbitals as valence electrons, we have constructed a high-quality projected augmented wave dataset that yields results comparable to existing full-potential linearized augmented plane-wave calculations. The dataset was then applied to BaFe 2 As 2 to study the effects of different levels of structure optimization, as well as different choices of exchange-correlation functionals. It was found that the local density approximation exchange-correlation functional fails to find the correct spin-density-wave anti-ferromagnetic (SDW-AFM) ground state under full optimization, while the Perdew–Burke–Ernzerhof (PBE) exchange-correlation functional obtains the correct state but significantly overestimates the magnetism. The electronic structure of the SDW-AFM state is not very sensitive to structure optimizations with the PBE exchange-correlation functional because the positions of the As atoms are preserved under optimizations. We further investigated the Ba atom diffusion process on the BaFe 2 As 2 surface using the nudged elastic bands method. The Ba atom was found to be stable above the center of the squares formed by the surface As atoms, and a diffusion barrier of 1.2 eV was found. Our simulated scanning tunneling microscopy image suggests an ordered surface Ba atom structure, in agreement with Massee et al (2009 Phys. Rev. B 80 140507; van Heumen E et al 2010 arXiv:1009.3493v1).
Source: New Journal of Physics
Authors: Chao Cao, Yu-ning Wu, Rashid Hamdan, Yun-Peng Wang, Hai-Ping Cheng
Institution: University of Florida
Language: English
Field: Materials Science
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,610
OpenAlex ID: W1966014551