Insight into the structural, elastic and electronic properties of a new orthorhombic 6O-SiC polytype
Yassine El Mendili, Beate Orberger, Daniel Chateigner, Jean‐François Bardeau, Stéphanie Gascoin, S. Petit, Olivier Pérez, Fouzia Khadraoui
Abstract
Abstract Different polytypes of SiC are described and predicted in literature. Here, we report the first occurrence of an orthorhombic 6O-SiC polytype as rock-forming mineral in the nickel laterite mine of Tiebaghi (New Caledonia). This new class of SiC crystallizes in the space group C mc 2 1 with 12 atoms per unit cell [a = 3.0778(6) Å, b = 5.335(2) Å, c = 15.1219(6) Å, α = 90°, β = 90°, γ = 120°]. The density of 6O-SiC is about 3.22 g/cm 3 and the calculated indirect bandgap at room temperature of 3.56 eV is identical to 6H-SiC. Our results suggest that 6O-SiC is the intermediate state in the wurtzite to rocksalt transformation of 6H-SiC.