PI-BONDED RECONSTRUCTIONS AT SI-TERMINATED AND C-TERMINATED SURFACES OF 2H-SIC - AN AB-INITIO MOLECULAR-DYNAMICS STUDY

We employ ab initio molecular dynamics to study pi-bonded reconstructi ons at Si- and C-terminated surfaces of wurzite SiC. We find that tota l energy is 0.38 eV and 0.68 eV lower per surface atom after the recon struction compared to (1 x 1) relaxed geometry at Si- and C-terminated surfaces, respectively. The Si-C pi-bonded chains are buckled and sli ghtly dimerized. At both surfaces, the outermost atoms are carbons, du e to the bond length constraints of the pi-bonded chain reconstruction . Surface states lie in the bulk energy gap between GAMMA and J of the primitive Surface Brillouin Zone, with surface energy gaps of 1.4 eV and 0.6 eV at J for the C- and Si-terminated surfaces, respectively.