Visualizing coexisting surface states in the weak and crystalline topological insulator BiTeI.

Dual topological materials are unique topological phases that host coexisting surface states of different topological nature on the same or on different material facets. Here, we show that BiTeI is a dual topological insulator. It exhibits band inversions at two time reversal symmetry points of the bulk band, which classify it as a weak topological insulator with metallic states on its 'side' surfaces.

A bismuth triiodide monosheet on BiSe(0001).

A stable BiI monosheet has been grown for the first time on the (0001) surface of the topological insulator BiSe as confirmed by scanning tunnelling microscopy, surface X-ray diffraction, and X-ray photoemision spectroscopy. BiI is deposited by molecular beam epitaxy from the crystalline BiTeI precursor that undergoes decomposition sublimation. The key fragment of the bulk BiI structure, [Formula: see text][I-Bi-I] layer of edge-sharing BiI octahedra, is preserved in the ultra-thin film limit, but exhibits large atomic relaxations.

Synthesis and Characterization of the New Manganese Hydroxide Chloride γ-Mn(OH)Cl.

A new modification of Mn(OH)Cl was obtained under high-pressure/high-temperature conditions in a Walker-type multianvil device. The pale pink, hygroscopic compound crystallizes in the orthorhombic space group (no. 62) with = 602.