A case study for the formation of stanene on a metal surface

The discovery and realization of graphene as an ideal two-dimensional (2D) material has triggered extensive efforts to create similar 2D materials with exciting spin-dependent properties. Here, we report on a novel Sn 2D superstructure on Au(111) that shows similarities and differences to the expected electronic features of ideal stanene. Using spin- and angle-resolved photoemission spectroscopy, we find that a particular Sn/Au superstructure reveals a linearly dispersing band centered at the Γ ¯ -point and below the Fermi level with anti-parallel spin polarization and a Fermi velocity of v_F ≈ 1×10⁶ m/s, the same value as for graphene. We attribute the origin of the band structure to the hybridization between the Sn and the Au orbitals at the 2D Sn-Au interface. Considering that free-standing stanene simply cannot exist, our investigated structure is an important step towards the search of useful stanene-like overstructures for future technological applications.