TY - JOUR
KW - paper
AU - Conor Hogan
AU - D Paget
AU - Y Garreau
AU - M Sauvage
AU - G Onida
AU - Lucia Reining
AU - P Chiaradia
AU - Corradini V
AB - We investigate the adsorption of Cs on the As-rich c(2x8)/(2x4) reconstruction of GaAs(001) at low coverages using a combination of theoretical and experimental techniques. Density-functional-theory local-density-approximation total-energy calculations and x-ray diffraction experiments find only minimal Cs-induced surface relaxation and identify three preferential adsorption sites within the partially disordered overlayer. These sites are, in order of decreasing occupation probability, the arsenic dimer bridge D site, the gallium dangling bond T-2(\textquoteright) site, and the arsenic T-3 trench site. Detailed analysis of the wave functions and electronic charge densities allows us to clarify the bonding mechanisms at the three sites. At the gallium site, the bonding is strongly ionic and involves significant charge transfer to a new Cs-induced state reminiscent of the p(z) orbital of the gallium atom in the sp(2) configuration. In sharp contrast, at the arsenic sites, the charge transfer is minimal and the bonding rather occurs through mixing with a relatively delocalized state of the clean surface. The ionization energy decreases are estimated and compared for the three sites.
BT - Phys. Rev. B
CY - ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA
DA - NOV
DO - 10.1103/PhysRevB.68.205313
M1 - 20
N2 - We investigate the adsorption of Cs on the As-rich c(2x8)/(2x4) reconstruction of GaAs(001) at low coverages using a combination of theoretical and experimental techniques. Density-functional-theory local-density-approximation total-energy calculations and x-ray diffraction experiments find only minimal Cs-induced surface relaxation and identify three preferential adsorption sites within the partially disordered overlayer. These sites are, in order of decreasing occupation probability, the arsenic dimer bridge D site, the gallium dangling bond T-2(\textquoteright) site, and the arsenic T-3 trench site. Detailed analysis of the wave functions and electronic charge densities allows us to clarify the bonding mechanisms at the three sites. At the gallium site, the bonding is strongly ionic and involves significant charge transfer to a new Cs-induced state reminiscent of the p(z) orbital of the gallium atom in the sp(2) configuration. In sharp contrast, at the arsenic sites, the charge transfer is minimal and the bonding rather occurs through mixing with a relatively delocalized state of the clean surface. The ionization energy decreases are estimated and compared for the three sites.
PB - AMERICAN PHYSICAL SOC
PP - ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA
PY - 2003
EP - 205313
T2 - Phys. Rev. B
TI - Early stages of cesium adsorption on the As-rich c(2x8) reconstruction of GaAs(001): Adsorption sites and Cs-induced chemical bonds
UR - http://dx.doi.org/10.1103/PhysRevB.68.205313
VL - 68
ER -