Regensburg 2016 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 17: 2D Materials: Structure and Electronic Properties
(Joint session of DS and O, organized by O)
DS 17.2: Vortrag
Dienstag, 8. März 2016, 10:45–11:00, H24
Structural, thermodynamic and electronic properties of two-dimensional SiC, SiGe, and GeC alloys — Ivan Guilhon1, Friedhelm Bechstedt2, •Ronaldo Rodrigues Pela1,3, Marcelo Marques1, and Lara Kuhl Teles1 — 1Instituto Tecnológico de Aeronáutica, São José dos Campos, Brazil — 2Institut für Festkörpertheorie und -optik, Friedrich-Schiller-Universität, Jena, Germany — 3Humboldt-Universität zu Berlin, Institut für Physik and IRIS Adlershof, Berlin, Germany
We investigate structural, thermodynamic, electronic properties of 2D binary alloys made from graphene, silicene and germanene by means of density functional theory calculations and a statistical method that accounts for disorder and compositional effects. The GGA-1/2 method [1] is used in electronic properties calculations to approximately include quasiparticle corrections. Si1−xGex is the only stable alloy at usual growth temperatures. In Ge1−xCx, strong distortions of the lattice lead to a pronounced tendency for phase separation. Si1−xCx presents an ordered structure with composition x=0.5 stable up to T≈ 1000 K. While Si1−xGex and Ge1−xCx are found to have vanishing band gaps, Si1−xCx has, around x=0.5, an appreciable band gap, which decreases exponentially with the growth temperature from ∼ 2.2 eV at 300 K to ∼ 1.2 eV at 900 K [2].
[1]: Phys. Rev. B 78, 125116 (2008); [2]: Phys. Rev. B 92, 075435 (2015).
Acknowledgments: “Conselho Nacional de Desenvolvimento Científico e Tecnológico” (CNPq), “Coordenação de Aperfeiçoamento de Pessoal de Nível Superior” (CAPES) and “Alexander von Humboldt Stiftung”.