Epitaxial growth of honeycomb-like stanene on Au(111)

Abstract

Stanene, which is predicted to be a quantum spin Hall topological insulator with tunable topological state, seems to be the most promising candidate of the post-graphene elemental two-dimensional (2D) materials. Here, we prepared epitaxial honeycomb-like stanene on gold (111) substrates and investigated its superstructure by Low Energy Electron Diffraction and Scanning Tunneling Microscopy. Angle-Resolved PhotoEmission Spectroscopy was applied to explore the electronic structures, further confirmed by first principles calculations. The stanene-like sheet forms a nearly planar structure on the Au(111) surface with a "2×√3" superstructure in large surface areas. Core-level spectroscopy reveals that the stanene-like sheet lays almost directly on the Au(111) surface. This is consistent with DFT calculations of the atomic structure. A characteristic 2D band with parabolic dis-persion is observed.

Growth of Open Honeycomb-like Sn Structures on Ag(111) at Low Temperatures

“…DFT calculations show that the formation of configurations with a combination of compact and open honeycomb-like structures is energetically favorable and that the formation of stanene on the Ag(111) surface can be ruled out. This is a result of the high stability of Sn adatoms with four neighbors, which have also been observed on other metallic surfaces. , The obtained DFT minimum energy configuration corresponds to a Sn coverage of 11 adatoms in the (4 × 4) supercell, in excellent agreement with the experimentally identified (4 × 4) unit cell.…”

“…Indeed, each one of the three atoms that form the triangle has four neighbors. These kinds of open structures combining Sn atoms with three and four neighbors are very stable and have also been reported on Cu(001) and recently on Au(111) …”

Phase Engineering of Epitaxial Stanene on a Surface Alloy

“…At low substrate temperature (330 K), the surface is fully covered by Sn tetramers and nanometer-sized aggregates (Figure a). The measured unit cell of the tetramer is 0.54 nm × 0.55 nm (close-up scan, bottom panel), which is close to the size of reported “honeycomb-like” stanene on Au(111) after RT deposition . Such tetramers and vacancies have also been observed in the Ge/Ag system that is driven by the structural coherent effect due to different types of chemical bonding .…”

Single-Element 2D Materials beyond Graphene: Methods of Epitaxial Synthesis

“…In one of the latest works [12], high-quality multilayer stanene with a thickness of one to five monolayers was successfully fabricated on PbTe (111) surface. In addition, stanene was fabricated on Cu (111) [56], MoS 2 [57], and Au (111) [58] surfaces.…”