Detailed analysis of impact collision ion scattering spectroscopy of bismuth selenide

Abstract

Impact collision ion scattering spectroscopy (ICISS), which is a variation of low energy ion scattering (LEIS) that employs large scattering angles, is performed on Bi 2 Se 3 surfaces prepared by ion bombardment and annealing. ICISS angular scans are collected experimentally and simulated numerically along the [120] and [ 1 20] azimuths, and the match of the positions of the flux peaks shows that the top three atomic layers are bulk-terminated. A newly observed feature is identified as a minimum in the multiple scattering background when the ion beam incidence is along a low index direction. Calculated scans as a function of scattering angle are employed to identify the behavior of flux peaks to show whether they originate from shadowing, blocking or both. This new method for analysis of large-angle LEIS data is shown to be useful for accurately investigating complex surface structures.

The growth of bismuth on Bi2Se3 and the stability of the first bilayer

“…Molecular dynamics (MD) simulations of ICISS are performed using the Kalypso software package [46] as done in previous work with Bi2Se3 [47]. The Thomas-Fermi-Molière repulsive potential using the Firsov screening length, corrected by a factor of 0.8, is used to calculate each projectile-target atom interaction.…”

Work function and surface stability of tungsten-based thermionic electron emission cathodes

“…28 [34][35][36][37][38] GaAs and Ge with adsorbed Cs, 39,40 and W and Sc 2 O 3 with adsorbed Ba-O. 12,13,[41][42][43] The emitting properties of W have been studied previously with Density Functional Theory (DFT)-based approaches, including the stability and work function of Ba, Sc and O on the (001) surface, 41 the expected crystal structures and electronic properties of Os-doped W, 44 and the stability and emission characteristics of W coated with various oxide films and adsorbed alkali metals. 45 However, an in-depth investigation examining the stability and work function of All calculations in this study were performed using Density Functional Theory (DFT) as implemented in the Vienna Ab-Initio Simulation Package (VASP).…”