Vacuum Ultraviolet Photoemission, the unique access to the
valence electronic structure of solid surfaces |
Photoemission of Si(001)
(961 KB mpeg movie) |
The photocurrent into the full hemisphere above the ideal Si(001)(1x1) surface
is calculated within the one-step theory for 4 polarizations of the
perpendicularly incident light. The large image shows the photoemission
intensities
from unpolarized light and the bottom left image for a polarization in
x direction. The third photoemission image contains the cirular
dichroism, the difference of the currents from left and right circularly
polarized light. All are constant final state spectra with a final state
energy of 49.5 eV. The intensity is projected onto the reciprocal space
with a polar angle of 90° at the outer border. The reciprocal lattice
is depicted by the white lines. The intensity of the currents is given by the
color, as shown by the color bar.
To compare with the electronic structure, the surface band
structure and the surface density of states are shown.
Along the high-symmetry path of the surface band structure, the density of
states is encoded by the color but, here dark green belonging to high
densities.
The blue area is the projected bulk band structure.
The surface density of states (SDOS) shown below for the same area of reciprocal
space as the photocurrent reflects the total density of states from all orbitals
of the four uppermost atoms.
For initial states at the surface J point iso-surfaces of the charge density
are shown at the bottom right. The charge density is blue and the positions of
the atoms are illustrated by green spheres.
Parallel to the surface one unit cell is shown with the
vacuum at the top followed by the first five atomic layers of the crystal.
For all these images the time parameter of the animation is the binding energy
as indicated by the vertical orange line in the band structure.
The iso-surfaces of the final charge densities at the top right belong to the
surface J points, too, but different emission angles are scanned during the
course of the movie. These are indicated
by the yellow dot in the surface density of states.
For the final states the upper nine atomic layers are shown.
The green pictogram gives the geometry of the unit cell with the uppermost
atoms larger than the the following ones.
See also:
- First calculated full-hemisphere valence band
photoemission intensities
- Calculation and physics of scattering
states
- Paper: C.-H. Solterbeck, W. Schattke, and C.S. Fadley,
Full-Hemisphere Valence
Band Photoemission Spectra Calculated for the Ideal Si(001)-Surface,
Surface Science 357-358, 245 (1996)
- Paper: W. Schattke,
Photoemission within and beyond the
one-step model,
Progr. Surf. Sci. 54, 211 (1997)
- Paper: C. Solterbeck, O. Tiedje, F. Starrost, and W. Schattke,
Scattering States for Very Low Energy
Electron Spectroscopy,
J. Electron Spectrosc. 88-91, 563 (1998)
- Poster: C. Solterbeck, O. Tiedje, F. Starrost, and W. Schattke,
Scattering States for Very Low Energy
Electron Spectroscopy, Poster 2P-63 at the 7th International
Conference on Electron Spectroscopy (ICES-7), September 8-12, 1997,
Chiba, Japan (gnuziped tar archive)
- Animation from 1998 with just the
photocurrent (510 KB mpeg movie)
- Animation from 1997 with the photocurrent
only into the frist quadrant (132 KB mpeg movie)
Acknowledgment:
This work was supported by the Bundesministerium für Bildung,
Wissenschaft, Forschung und Technologie
(Project No. 05 605 FKA).
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