Formation of planar stanene epitaxially grown on Ag(111)

The heavy group 14 elements (Si, Ge, Sn) have received great attention as candidates of post-graphene materials [1-3]. Recently, the synthesis of Sn-based highly buckled stanene on Bi₂Te₃(111) has been reported [3]. In the present study, we report a planar stanene prepared on Ag(111), which we have investigated using combined experimental techniques and ab initio calculations. The high-resolution STM images clearly exhibit large area planar stanene with honeycomb structure. From PES spectra, it is identified that Ag 3d_5/2 exhibits a new component at higher binding energy than for the initially formed Ag₂Sn surface alloy. The Sn 4d spectra exhibit a single component for the Ag₂Sn alloy and two specific components for stanene grown on Ag(111). A parabolic electronic band is observed in the ARPES measurements. This electronic signature is rather consistently reproduced in the band structure of stanene on Ag(111) calculated using DFT calculations. These results establish that planar stanene, potentially a room temperature topological insulator, is formed on Ag(111) substrate.

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[2] M. E. Dávila et al., New Journal of Physics 16 (2014) 095002
[3] Feng-feng Zhu et al., Nature Materials 14 (2015) 10