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Free keywords:
Bismuth bilayer
Bismuth selenide
Iron selenide
Scanning tunneling microscopy
Topological insulator/superconductor heterostructures
Abstract:
Procedures for the preparation of Bi2Se3(0001) surfaces, FeSe atomic layers, and Bi bilayers on Bi2Se3(0001) are presented. Bi2Se3(0001) surfaces are characterized by terraces separated by quintuple layer high steps of 0.95 nm height. Epitaxial FeSe islands with lateral extensions of several hundred nanometers and a few unit cell (nm) thickness are produced by Fe deposition at room temperature and subsequent annealing at 650 K. These islands are under an anisotropic in-plane strain (a=0.377±0.002 nm, b=0.385±0.004 nm) with respect to the bulk FeSe reference state (aFeSE,bulk=0.377 nm). Bi bilayers are formed on Bi2Se3(0001) by atomic hydrogen plasma etching, which removes Se from the Bi2Se3 sample surface. Scanning tunneling microscopy and scanning tunneling spectroscopy are used to characterize the Bi2Se3 substrate and the nanostructures formed on its surface. A differential conductance peak near V identifies a defect-free Bi bilayer on Bi2Se3(0001).