Identifying crystal structures and chemical reactions at the interface of stanene on Bi₂Te₃

Synthesizing monolayers and heterostructures is an enabling approach to extract new physical phenomena from bulk materials. Among the structures amenable to this approach is stanene, which is a monolayer of tin, similar to graphene, and has been predicted to host one-dimensional topological states at its edges. Stanene can be tuned by decorating with different adatoms, which makes it a promising platform on which to engineer topological devices. Here, we deposit Sn on Bi₂Te₃ and characterize the growth using anomalous synchrotron x-ray scattering and x-ray photoelectron spectroscopy (XPS). X-ray diffraction data reveal the formation of epitaxial Sn-based structures, along with penetration of Sn into the Bi₂Te₃, with Sn intercalating between the upper 10 Bi₂Te₃ quintuple layers. Additionally, XPS data show deposited Sn reacting to form SnTe and Bi at the Bi₂Te₃ surface. The calculated heat of reaction for Sn and Bi₂Te₃ is consistent with an exothermic reaction to SnTe and Bi. Using thermodynamic calculations as a guide, we identify several candidate substrates that can stabilize the stanene phase.