Berlin 2018 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 113: 2D materials beyond graphene: TMDCs, silicene and relatives V
O 113.10: Vortrag
Freitag, 16. März 2018, 12:45–13:00, MA 043
Structural prediction of two-dimensional materials under strain — •Pedro Borlido1, Conrad Steigemann2, Nektarios Lathiotakis3, Claudia Rödl1, Miguel Marques2, and Silvana Botti1 — 1Institut für Festkörpertheorie und -optik, Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, 07743 Jena, Germany — 2Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, D-06099 Halle, Germany — 3Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, GR-11635 Athens, Greece
Using a constrained global structural prediction method we performed an extensive investigation of the low density phases of two-dimensional carbon and silicon. As expected, we find that graphene is stable for a large range of biaxial strains, while more complex configurations becoming energetically more favorable at areas per atom above 3.12 Å2. Two dimensional silicon presents a more complex phase diagram, which includes both haeckelite-like structures and dumbbell configurations. In particular, we find as the groundstate of two-dimensional silicon a novel structure formed by a honeycomb lattice with a few strategically positioned dumbbell atoms. This material is 218 meV/atom more stable than silicene and is a quasi-direct semiconductor with a band gap of around 1.11 eV and a very dispersive electron band. These properties should make it easier to synthesize than pristine silicene and interesting for a wealth of opto-electronic applications.