Scanning Tunneling Microscopy Study of Free-Standing-Like Stanene on InSb(111)A
ORAL
Abstract
Stanene is a tin (Sn) based two-dimensional material with a buckled honeycomb structure, potentially showing quantum spin Hall effect at room temperature (RT). Although there are several reports on experimental studies on stanene formed on substrates, the reported electronic states are different from those predicted for the free-standing stanene due to the structural difference and the interaction with substrates. In this study, growth conditions for a free-standing-like stanene on In-polar indium antimonide wafer, InSb(111)A, were investigated as its in-plane lattice constant is very close to that of free-standing stanene.
The growth and analysis were carried out in an Omicron ultra-high vacuum scanning probe microscopy system. Substrates were cleaned by Ar ion sputtering and subsequent annealing at 730 K to form clean (2×2)-reconstructed surface. Sn were evaporated on this surface kept at RT with a deposition rate of 0.12 monolayer (ML, 1 ML = 1.056×1015 atoms/cm2) per minute. The samples were annealed after Sn deposition. Scanning tunneling microscopy (STM) images were obtained at RT using W tip.
Sn deposition of 0.62 ML and post-annealing at 680-730 K for 5 minutes resulted in regions covered by a hexagonal domain structure. Inside the domains, a honeycomb structure was observed, whose lattice constant is very close to that expected for a free-standing stanene. This observation suggests that InSb(111)A is a suitable substrate for the stabilization of free-standing-like stanene.
The growth and analysis were carried out in an Omicron ultra-high vacuum scanning probe microscopy system. Substrates were cleaned by Ar ion sputtering and subsequent annealing at 730 K to form clean (2×2)-reconstructed surface. Sn were evaporated on this surface kept at RT with a deposition rate of 0.12 monolayer (ML, 1 ML = 1.056×1015 atoms/cm2) per minute. The samples were annealed after Sn deposition. Scanning tunneling microscopy (STM) images were obtained at RT using W tip.
Sn deposition of 0.62 ML and post-annealing at 680-730 K for 5 minutes resulted in regions covered by a hexagonal domain structure. Inside the domains, a honeycomb structure was observed, whose lattice constant is very close to that expected for a free-standing stanene. This observation suggests that InSb(111)A is a suitable substrate for the stabilization of free-standing-like stanene.
*This work was supported by JST SPRING, Japan GrantNumber JPMJSP2102 and JSPS KAKENHI Grant NumbersJP20H00328 and JP21H05236.
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Presenters
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Takato Yokoo
- Japan Adv Inst of Sci and Tech