Empty electronic states of epitaxial Bi overlayers on InP(110): Effects of surface relaxation

Abstract

Momentum‐resolved inverse photoemission (KRIPES) and low energy electron diffraction (LEED) have been used to investigate the development at 300 K of the unoccupied electronic states and the overlayer morphology for growth of up to 15 ML of Bi on InP(110). KRIPES results reveal a Bi‐derived surface state at EF+1.35 eV on p‐type InP(110) for 1 monolayer (ML) coverage. This state is associated with zig–zag chain formation along the [110] direction. The LEED seen for coverages above ∼6 ML suggests the formation of ordered Bi bulk‐like patches atop the initial monolayer with the crystallite basal planes oriented parallel to the relaxed InP(110) surface. The structure of the ordered, bulk‐like Bi patches originates from the two inequivalent sites for 1 ML Bi/InP(110), namely Bi–In and Bi–P bonding. The basal planes of the Bi crystallites are ∼20° from the normal of the unrelaxed (110) surface, toward [001]. The large InP(110) surface relaxation remaining after 1 ML growth of Bi and the slow strain relief upon...