2D Tl-Pb compounds on Ge(1 1 1) surface: Atomic arrangement and electronic band structure
Journal
Journal of Physics Condensed Matter
Journal Volume
29
Journal Issue
3
ISSN
09538984
Date Issued
2017
Author(s)
Gruznev, D.V.
Bondarenko, L.V.
Tupchaya, A.Y.
Eremeev, S.V.
Mihalyuk, A.N.
Wei, C.M.
Zotov, A.V.
Saranin, A.A.
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), √3 × √3-(Tl, Pb) and 3 × 3-(Tl, Pb), have been found and their composition, atomic arrangement and electron properties has been characterized. The (Tl, Pb)/Ge(1 1 1) √3 × √3 compound is almost identical to the alike (Tl, Pb)/Si(1 1 1) √3 × √3 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)3 × 3 compound contains six Tl atoms and seven Pb atoms per 3 × 3 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) √3 × √3 and (Tl, Pb)/Ge(1 1 1) 3 × 3 compounds are metallic and their band structures contain spin-split surface-state bands. By analogy with the (Tl, Pb)/Si(1 1 1) √3 × √3, these (Tl, Pb)/Ge(1 1 1) compounds are believed to be promising objects for prospective studies of superconductivity in one-atom-layer systems. © 2016 IOP Publishing Ltd.
Subjects
2D layer
ARPES
atom-solid interaction
DFT calculations
electronic structure
STM
Publisher
Institute of Physics Publishing
Type
journal article