Ab initio and scanning tunneling microscopy study of an indium-terminated GaAs(100) surface: An indium-induced surface reconstruction change in the c(8x2) structure
2010 (English)In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 81, no 24, 245305- p.Article in journal (Refereed) Published
Technologically useful indium- (In) terminated c(8 x 2)-reconstructed GaAs(100) substrate surface has been studied by first-principles calculations and scanning tunneling microscopy (STM) measurements. Our total-energy calculations demonstrate the stability of four different so-called zeta a structures with In monomer rows and In coverage between 0.5 and 2 monolayers on the GaAs(100) substrate. Thus, we introduce a surface system, which stabilizes the zeta a reconstruction. Furthermore, an interesting trend is found. Atomic structure of the c(8 x 2) reconstruction depends on the surface-layer cation and substrate volumes, which, in principle, allows to tune the surface structure by cation adsorption. This phenomenon is related to the peculiar c(8 x 2) atomic surface structure, which shows mixed surface layer, including both anions and cations, and uncommon metallic-type cations in the zeta a structure, which do not show covalent bonds. Our results predict a structural transition from the zeta structure to the zeta a structure as the surface cation size is increased at 0 K. The found transition is probably related to the disordered surface structures (consisting of zeta and zeta a building blocks) found experimentally by x-ray diffraction at room temperature. Comparison of the STM images, calculated for various c(8 x 2) models, with the former and present measured STM images of In/GaAs(100) c(8 x 2) supports the presence of stable zeta a reconstructions.
Place, publisher, year, edition, pages
2010. Vol. 81, no 24, 245305- p.
Condensed Matter Physics
IdentifiersURN: urn:nbn:se:kth:diva-27317DOI: 10.1103/PhysRevB.81.245305ISI: 000278483200004ScopusID: 2-s2.0-77956322610OAI: oai:DiVA.org:kth-27317DiVA: diva2:376021
QC 201012092010-12-092010-12-092010-12-09Bibliographically approved