Spatial origin of photoelectrons

GaAs(110)

Photocurrent and charge density

Photocurrent for E_in = -4.0 eV and k_|| = 0.6 Å^-1: (a) measured (green) and calculated (magenta) current with radius representing the intensity in the polar plot; (b)+(c) partial currents emerging from the middle (b), and the outer (c) area, as indicated in (d). (d) Contour plot of the charge density in a plane through the the uppermost As and Ga atoms, calculated for the initial state belonging to the upper right lobe at 15° in (a).

ARUPS probes the bonding region.

Charge density of final and initial state

Iso-surfaces of the charge for E_in and k_|| as above: the final charges (a)+(c) belong to the photocurrent at 195° (a) and 15° (c), the charge density in (b) is that of the initial state for both of these peaks. The frames indicate the unit cell in the topmost atomic planes. The vacuum is above the frames. The higher values of the charges are enclosed by the iso-surfaces.

Large contributions to the current can be expected from areas with joint strong densities of the initial and final charge distribution.

Claus-Henning Solterbeck, for references see here.

CAU Kiel Physics Theory Home Frontiers 30.5.1998