European Physical Journal B: Condensed Matter and Complex Systems

Autor: Almeida Junior, Edward Ferraz de, Mota, F. de Brito, Castilho, Caio Mário Castro de, Georgieva, A. Kakanakova, Gueorguiev, G. K.
Jazyk: angličtina
Rok vydání: 2012
Předmět:
Zdroj: Repositório Institucional da UFBA
Universidade Federal da Bahia (UFBA)
instacron:UFBA
DOI: 10.1140/epjb/e2011-20538-6
Popis: Texto completo: acesso restrito. p. 1-9 Submitted by Edileide Reis (leyde-landy@hotmail.com) on 2014-08-27T11:33:49Z No. of bitstreams: 1 E. F. de Almeida Jr..pdf: 1808859 bytes, checksum: 4b342c44b42cd6127ddd3d469e5f5f53 (MD5) Approved for entry into archive by Patricia Barroso (pbarroso@ufba.br) on 2014-08-28T21:27:26Z (GMT) No. of bitstreams: 1 E. F. de Almeida Jr..pdf: 1808859 bytes, checksum: 4b342c44b42cd6127ddd3d469e5f5f53 (MD5) Made available in DSpace on 2014-08-28T21:27:27Z (GMT). No. of bitstreams: 1 E. F. de Almeida Jr..pdf: 1808859 bytes, checksum: 4b342c44b42cd6127ddd3d469e5f5f53 (MD5) Previous issue date: 2012 Theoretical calculations focused on the stability of an infinite hexagonal AlN (h-AlN) sheet and its structural and electronic properties were carried out within the framework of DFT at the GGA-PBE level of theory. For the simulations, an h-AlN sheet model system consisting in 96 atoms per super-cell has been adopted. For h-AlN, we predict an Al-N bond length of 1.82 Å and an indirect gap of 2.81 eV as well as a cohesive energy which is by 6% lower than that of the bulk (wurtzite) AlN which can be seen as a qualitative indication for synthesizability of individual h-AlN sheets. Besides the study of a perfect h-AlN sheet, also the most typical defects, namely, vacancies, anti-site defects and impurities were also explored. The formation energies for these defects were calculated together with the total density of states and the corresponding projected states were also evaluated. The charge density in the region of the defects was also addressed. Energetically, the anti-site defects are the most costly, while the impurity defects are the most favorable, especially so for the defects arising from Si impurities. Defects such as nitrogen vacancies and Si impurities lead to a breaking of the planar shape of the h-AlN sheet and in some cases to the formation of new bonds. The defects significantly change the band structure in the vicinity of the Fermi level in comparison to the band structure of the perfect h-AlN which can be used for deliberately tailoring the electronic properties of individual h-AlN sheets.
Databáze: OpenAIRE
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