A new (2 × 1) reconstructed edge structure of zigzag Si nanoribbon: first principles study.
Based upon the first principles calculations, a new (2 × 1) reconstructed edge structure (edge-4) with a triangle-pentagon pair topological defect at its edges is found for the zigzag Si nanoribbon, which is different from the previously found ones (edge-2 and edge-3) and more stable in energy than them. More interestingly, it is found that the edge-2 and edge-3 can transform into the new edge-4 under a little bit compression force along the ribbon edge, and the edge-4 could also be transformed into the edge-3 by a tensile strain larger than 9%. The calculated vibrational modes of the edge-4 show that two new characteristic vibrational edge defect modes appear at 434 cm(-1) and 515 cm(-1), which could be used in experiment to distinguish easily the new edge-4 from the edge-2 and edge-3. Finally, a sharp peak near the Fermi level is found to exist in the projected density of states from the edge's pz orbital of edge-4, making its energy bands spin-split and the antiferromagnetic state to be its ground state.
Group of Computational Condensed Matter Physics, National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, People's Republic of China.
Rui
R
Li
Jian
J
Zhou
Yang
Y
Han
Jinming
J
Dong
Yoshiyuki
Y
Kawazoe