Ab initio simulations of the structural phase transformation of 2H-SiC at high pressure

Durandurdu M.

PHYSICAL REVIEW B, vol.75, no.23, 2007 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 75 Issue: 23
  • Publication Date: 2007
  • Doi Number: 10.1103/physrevb.75.235204
  • Journal Name: PHYSICAL REVIEW B
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Abdullah Gül University Affiliated: No


We study the pressure-induced phase transition in the 2H-SiC (wurtzite) using a constant-pressure ab initio technique. A first-order phase transition from the wurtzite structure to a rocksalt structure at 600.0-700.0 GPa is predicted in the constant-pressure simulations. The transformation consists of two successive processes. First, the wurtzite crystal transforms into a fivefold coordinated hexagonal structure with space group P6(3)/mmc due to a compression in the direction of the c axis. Second, the hexagonal phase becomes unstable with respect to shear deformation and converts to first a fivefold coordinated orthorhombic intermediate state within the Cmcm symmetry, and then a rocksalt state. We also study the wurtzite-to-rocksalt and zinc-blende-to-rocksalt phase transformations of SiC from the enthalpy calculations and find that both zinc-blende and wurtzite SiC polytypes show nearly similar equation of state and transforms to a rocksalt structure about 100.0 GPa, in excellent agreement with experiments.