title: Step structures on III-V phosphide (001) surfaces: how do steps and Sb affect CuPt ordering of GaInP2?
abstract: The observation of III-V phosphide (001)-(2 x 2) surfaces makes it possible to solve a long standing mystery of step structures. First-principles calculations show that a bulklike type-B step on a hydrogenated 2 x 2 surface is more stable than a rebonded one by 1.1 eV/unit step. In contrast, this energy difference for a H-free beta(2 x 4) surface is only 0.5 eV/unit step. The large difference explains why the CuPt ordering of GaInP is stronger in metal-organic chemical vapor deposition than in molecular beam epitaxy. However, a minute amount of Sb will preferentially attach to the 2 x 2 surface steps and induce additional step structures that cause ordering disruption.
authors.affiliation: National Renewable Energy Laboratory, Golden, Colorado 80401, USA.
authors.forename: Iskander G
authors.initials: IG
authors.lastname: Batyrev
authors.forename: W E
authors.initials: WE
authors.lastname: McMahon
authors.forename: S B
authors.initials: SB
authors.lastname: Zhang
authors.forename: J M
authors.initials: JM
authors.lastname: Olson
authors.forename: Su-Huai
authors.initials: SH
authors.lastname: Wei