Surface structure of in situ cleaved single crystal Bi2Se3 measured by low energy ion scattering

Abstract

Bismuth selenide is a two-dimensional topological insulator material composed of stacked quintuple layers (QL). The layers are held together by a weak van der Waals force that enables surface preparation by cleaving. Low energy ion scattering experiments show that Bi2Se3 cleaved under ultrahigh vacuum has a Se-terminated structure that is consistent with cleaving between QLs. Comparison of experimental data to molecular dynamics simulations confirms the Se-termination and provides an estimate of the surface relaxation.