A bismuth triiodide monosheet on Bi 2 Se 3 (0001).

Authors :: Polyakov A
Mohseni K
Castro GR
Rubio-Zuazo J
Zeugner A
Isaeva A
Chen YJ
Tusche C
Meyerheim HL
Source :: Scientific reports [Sci Rep] 2019 Mar 11; Vol. 9 (1), pp. 4052. Date of Electronic Publication: 2019 Mar 11.
Publication Year :: 2019
Abstract: A stable BiI <subscript>3</subscript> monosheet has been grown for the first time on the (0001) surface of the topological insulator Bi <subscript>2</subscript> Se <subscript>3</subscript> as confirmed by scanning tunnelling microscopy, surface X-ray diffraction, and X-ray photoemision spectroscopy. BiI <subscript>3</subscript> is deposited by molecular beam epitaxy from the crystalline BiTeI precursor that undergoes decomposition sublimation. The key fragment of the bulk BiI <subscript>3</subscript> structure, [Formula: see text][I-Bi-I] layer of edge-sharing BiI <subscript>6</subscript> octahedra, is preserved in the ultra-thin film limit, but exhibits large atomic relaxations. The stacking sequence of the trilayers and alternations of the Bi-I distances in the monosheet are the same as in the bulk BiI <subscript>3</subscript> structure. Momentum resolved photoemission spectroscopy indicates a direct band gap of 1.2 eV. The Dirac surface state is completely destroyed and a new flat band appears in the band gap of the BiI <subscript>3</subscript> film that could be interpreted as an interface state.