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MM: Fachverband Metall- und Materialphysik

MM 59: Phase Transitions I

MM 59.3: Vortrag

Donnerstag, 25. März 2010, 14:30–14:45, H5

Bonding in boron: building high-pressure phases from boron sheets — •Jens Kunstmann¹, Lilia Boeri², and Jens Kortus³ — ¹Institute for Materials Science and Max Bergmann Center of Biomaterials, Dresden University of Technology, Germany — ²Max Planck Institute for Solid State Research, Stuttgart, Germany — ³Institute for Theoretical Physics, TU Bergakademie Freiberg, Germany

We present the results of a study of the high pressure phase diagram of elemental boron, using full-potential density functional calculations. We show that at high pressures (P > 100 GPa) boron crystallizes in quasi-layered bulk phases, characterized by in-plane multicenter bonds and out-of-plane unidimensional sigma bonds. These structures are all metallic, in contrast to the low-pressure icosahedral ones, which are semiconducting. We show that the structure and bonding of layered bulk phases can be easily described in terms of single puckered boron sheets [1]. Our results bridge the gap between boron nanostructures and bulk phases. [1] Kunstmann et al., Phys. Rev. B 74, 035413 (2006).