Electrons on the Si (001) Surface
Electrons and Atoms Dancing on the
Si(001) Surface: A Video of First Principles
Molecular Dynamics (in full length)
mpeg (7.7 MB)
Electron Density in the top surface layers. Evolution of the
dangling bonds above the top-layer atoms at asymmetric dimers
Abstract
In this project the ab initio molecular dynamics in the
Car-Parrinello formulation has been applied to study the microscopic
processes in semiconducting materials and the scientific visualization
tools have been developed in order to animate the emerging dynamical
picture. These tools can now be offered to all CSCS users performing
the MD simulations for solid state physics and materials science.The
coupled evolution of the atomic positions and of the electronicdensity
of the highest occupied states on the Si(001) surface have been studied
by first-principles molecular dynamics. A video sequence illustrating
the time-dependent changes accompanying the anharmonic flipping of dimers
in the top layer has been generated. The experimental facts that at room
temperature the dimers appear symmetric in scanning tunnelling microscope
topographic images, whereas at low temperatures (T<120K) dimers appear
tilted are confirmed. Similar molecular dynamics calculations will be extended
to defects and to alkali-metal adsorbed on the same silicon surface.
Involved Persons:
A. Baratoff: Institut fuer Physik, Universitaet Basel
E.P. Stoll: Physik Institut, Universitaet Zuerich
A. Mangili: CSCS/SCSC
D.Maric: CSCS/SCSC