title: 2D Tl-Pb compounds on Ge(1 1 1) surface: atomic arrangement and electronic band structure.
abstract: Structural transformations and evolution of the electron band structure in the (Tl, Pb)/Ge(1 1 1) system have been studied using low-energy electron diffraction, scanning tunneling microscopy, angle-resolved photoelectron spectroscopy and density functional theory calculations. The two 2D Tl-Pb compounds on Ge(1 1 1), [Formula: see text]-(Tl, Pb) and [Formula: see text]-(Tl, Pb), have been found and their composition, atomic arrangement and electron properties has been characterized. The (Tl, Pb)/Ge(1 1 1)[Formula: see text] compound is almost identical to the alike (Tl, Pb)/Si(1 1 1)[Formula: see text] system from the viewpoint of its atomic structure and electronic properties. They contain 1.0 ML of Tl atoms arranged into a honeycomb network of chained trimers and 1/3 ML of Pb atoms occupying the centers of the honeycomb units. The (Tl, Pb)/Ge(1 1 1)[Formula: see text] compound contains six Tl atoms and seven Pb atoms per [Formula: see text] unit cell (i.e.  ∼0.67 ML Tl and  ∼0.78 ML Pb). Its atomic structure can be visualized as consisting of Pb hexagons surrounded by Tl trimers. The (Tl, Pb)/Ge(1 1 1)[Formula: see text] and (Tl, Pb)/Ge(1 1 1)[Formula: see text] compounds are metallic and their band structures contain spin-split surface-state bands. By analogy with the (Tl, Pb)/Si(1 1 1)[Formula: see text], these (Tl, Pb)/Ge(1 1 1) compounds are believed to be promising objects for prospective studies of superconductivity in one-atom-layer systems.
authors.affiliation: Institute of Automation and Control Processes FEB RAS, 690041 Vladivostok, Russia. School of Natural Sciences, Far Eastern Federal University, 690950 Vladivostok, Russia.
authors.forename: D V
authors.initials: DV
authors.lastname: Gruznev
authors.forename: L V
authors.initials: LV
authors.lastname: Bondarenko
authors.forename: A Y
authors.initials: AY
authors.lastname: Tupchaya
authors.forename: S V
authors.initials: SV
authors.lastname: Eremeev
authors.forename: A N
authors.initials: AN
authors.lastname: Mihalyuk
authors.forename: J P
authors.initials: JP
authors.lastname: Chou
authors.forename: C M
authors.initials: CM
authors.lastname: Wei
authors.forename: A V
authors.initials: AV
authors.lastname: Zotov
authors.forename: A A
authors.initials: AA
authors.lastname: Saranin