Volume 86, Number 3, May 2009
Article Number 36003
Section Condensed Matter: Structural, Mechanical and Thermal Properties
Published online 18 May 2009
EPL, 86 (2009) 36003
DOI: 10.1209/0295-5075/86/36003

Effects of charged surface states on Sb ad-dimer rotation on Si(001)

Jian Zhao and J. G. Che

Surface Physics Laboratory (National Key Laboratory) and Department of Physics, Fudan University Shanghai 200433, PRC

received 19 January 2009; accepted in final form 2 April 2009; published May 2009
published online 18 May 2009

Based on first-principles calculations, we identify a two-stage process for the rotation of Sb ad-dimer on Si(001). The bond between Sb and Si, which is broken over transition states in the rotation pathway, undergoes changes from $\sigma $ bonding to $\pi $ bonding near the transition states. Being close to the Fermi level, these $\pi $ states are sensitive to an external electric field, and thus may play a role in understanding the reversible rotation of the Sb ad-dimer between two orthogonal orientated states on Si(001) observed by scanning tunneling microscopy.

68.43.Bc - Ab initio calculations of adsorbate structure and reactions.
68.43.Jk - Diffusion of adsorbates, kinetics of coarsening and aggregation.
68.43.Fg - Adsorbate structure (binding sites, geometry).

© EPLA 2009