A comparative DFT study of the structural and electronic properties of nonpolar GaN surfaces
2014; Elsevier BV; Volume: 314; Linguagem: Inglês
10.1016/j.apsusc.2014.07.077
ISSN1873-5584
AutoresRafael González‐Hernández, Álvaro González-García, Daniel Barragán-Yani, William López‐Pérez,
Tópico(s)Ga2O3 and related materials
ResumoA comparative analysis of the geometry and the electronic characteristics of nonpolar GaN surfaces was carried out using density-functional theory (DFT) with different approximations for the exchange-correlation energy (LDA, PBE, PBEsol, RPBE, TPSS, revTPSS, and HSE). The obtained data show that the GaN(101¯0) (m-plane) is more energetically stable than the GaN(112¯0) (a-plane) surface. However, these surfaces have similar surface relaxation geometry, with a Ga-N surface bond-length contraction of around 6–7% and a Ga-N surface rotational angle in the range of 6–9°. Our results show that the use of different exchange-correlation functionals does not significantly change the surface energy and surface geometry. In addition, we found the presence of surface intra-gap states that reduce the band gap of the nonpolar GaN surface with respect to the bulk value, in agreement with recent photoelectron and surface optical spectroscopy experiments.
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