Magnetic Assembly of Co Atoms on 2D alpha-Sn Topological Insulator

Chia-Ju Chen^1*, Shih-Tang Huang¹, Yen-Hui Lin¹, Ta-Yu Yeh¹, Deng-Sung Lin¹, Ye-Shun Lan¹, Angus Huang¹, Horng-Tay Jeng¹, Pin-Jui Hsu¹

¹Department of Physics, National Tsing Hua University, Hsinchu, Taiwan

* Presenter:Chia-Ju Chen, email:d8546842123@yahoo.com.tw

A 2D topological insulator is a promising candidate for realizing the quantum spin Hall effect. Due to the time-reversal symmetry, the backscattering channel is forbidden on the robustness edge state gives rise to dissipationless electric conduction. Stanene is a promising material with various properties that have been reported with large quantum spin/anomalous Hall gaps (~0.3 eV) at room temperature and have been discovered superconductivity in a few-layer thickness. In this study, we deposit a small amount of Co atoms onto the submonolayer flat islands of α-Sn (stanene) on the Cu(111) by the low temperature growth. By utilizing scanning tunneling microscopy/spectroscopy techniques, the topographic images show Co atoms form the triangular trimers and dumbbell dimers on the top of the stanene islands. Besides, the differential conductance spectra taken on the Co atoms reveal a distinct peak at -0.3 eV, which has been theoretically indicated as an occupied minority d_z² -like spin-polarized surface state. The self-assembled Co atoms may offer an interesting way to artificially build up local magnetic properties on top of the monolayer stanene down to the atomic scale.

Keywords: 2D Topological Insulator, Stanene, Self-assembled Co atoms