Eur. Phys. J. B (2012) 85: 373
https://doi.org/10.1140/epjb/e2012-30520-5

Regular Article

New hexagonal structure for silicon atoms

¹ LMPHE, (URAC 12), Faculté des Sciences, Université Mohammed V-Agdal, Rabat, Morocco
² Department of Physics, Faculty of Science, Ibb University, Ibb, Yemen
³ Centre National de l’Energie, des Sciences et des Techniques Nucléaires, Rabat, Morocco
⁴ Centre of Physics and Mathematics, CPM-CNESTEN, Rabat, Morocco
⁵ Institute of Nanomaterials and Nanotechnology, MAScIR, Rabat, Morocco
⁶ Hassan II Academy of Science and Technology, Rabat, Morocco

^a e-mail: elkenz@fsr.ac.ma

Received: 8 May 2012
Received in final form: 5 September 2012
Published online: 19 November 2012

Abstract

Motivated by recent experimental and theoretical works on silicene and its derived materials and based on the exceptional Lie algebra G₂ we propose a new hexagonal symmetry producing the (√3 × √3)R30° superstructure for silicon atoms. The principal hexagonal unit cell contains twelve atoms instead of the usual structure involving only six ones and it is associated with the G₂ root system. In this silicon atom configuration appears two hexagons of unequal side length at angle 30°. This atomic structure can be tessellated to exhibit two superstructures (1 × 1) and (√3 × √3)R30° on the same atomic sheet. To test this double hexagonal structure, we perform a numerical study using Ab-initio calculations based on FPLO9.00-34 code. We observe that the usual silicon electronic properties and the lattice parameters of planar geometry are modified. In particular, the corresponding material becomes a conductor rather than zero gaped semi-conductor arising in single hexagonal structure. Although the calculation is done for silicon atoms, we expect that this structure could be adapted to all two dimensional materials having a single hexagonal flat geometry.