磁性原子摻雜系統一直是凝態領域上熱門的研究之一，改變原系統能帶結構
引發出不同的效應，如磁性摻雜拓樸絕緣體，破壞了時間反演對稱性進而引發反
常量子霍爾效應，所有邊界態電子僅有單一傳輸方向，且具有隨磁場強度變化形
成的階梯化橫向電阻與趨近於零的縱向電阻；磁性原子摻雜於超導，庫柏電子對
與磁性原子帶有的自旋極化作結合產生拓樸超導體，有機會於邊界觀測馬約拉那
束縛態的特徵。
經2010 年文獻已知Pb on Si(111)些許重構具有超導，本實驗是研究Pb c(8×4)
於Si(100)鍍上Mn 後使用掃描式穿隧電子顯微鏡觀察表面結構，從系統化的製
備方式能夠於Si(100)生長出整齊平整的Pb c(8×4)重構，在低溫100K 下摻雜少
量Mn 原子進行77K 實驗觀測，從STM 地形圖觀察到 Mn 原子與Pb c(8×4)重
構結合且具有兩種分布模式，而後對此提出實驗模型後進行DFT 計算，對比下
來實驗與理論計算結果非常相似，而計算也表示此系統也在鍍上Mn 後帶有磁性。
另一方面，於0.3K 下量測c(4×4)於Si(100)，從掃描穿隧能譜結果表示此系統能
隙大小隨著溫度下降而增加，表明了此系統不帶有超導，而c(8×4)鍍量比c(4×4)
來得更小，推估c(8×4)帶有超導的可能性不高。
低溫成長Sn 單層薄膜於Cu(111)基板形成蜂窩狀結構Stanene 已有文獻研究
表明為拓樸絕緣體，對其系統摻雜少量磁性Co 原子，並使用掃描穿隧電子顯微
鏡進行於4K 低溫觀察量測，實驗觀察Co 原子於Stanene 島嶼表面分別形成單
體(Monomer)、二聚體(Dimer)、三聚體(Trimer)三種簡單結構，在4K 掃描穿隧能
譜的量測發現Monomer 在-0.1V，Dimer 和Trimer 在-0.3V 有一明顯的峰值，相
比於Stanene 表面STS 證實這些峰值是因Co 自組裝結構而產生，從文獻已知Co
原子在Cu(111)帶有自旋磁矩，若這些自組裝結構中間隔著單層Sn 島嶼仍然帶
有磁矩，可為未來探討磁性雜質與二維拓樸絕緣體間的交互作用的研究提供了一
個結構單純，方便量測的理想實驗系統。

Magnetic-impurity doped systems have been one of the hottest research in the field of
condensed matter and different effects show up since magnetic impurity changes the
original system’s band structure. In a magnetic-impurity-doped topological insulator,
breaking the time-reversal symmetry (TRS) gives rise to Quantum anomalous hall
effect (QAH). Only one transfer direction is allowed for the edge-state electrons, at the
same time longitudinal resistance approaches zero and Hall (widthwise) resistance
changes from a straight line to an obvious platform step-like function by increasing
magnetic field. In a Magnetic-impurity-doped superconductor, the interaction of
Cooper pair and spin of magnetic atom gives rise to a topological superconductor, and
there is an opportunity to observe the characteristics of Majorana bound state at the
boundary.
From the paper published in 2010, we know that Pb on Si(111) shows superconductivity
in some Pb reconstructions. In this work, we have investigated Mn deposited at low
temperature (about 100 K) on Pb-c(8 × 4)/Si(100) by using scanning tunneling
microscopy (STM). Results show that self-assembled Mn atoms combine with Pb
c(8×4) and have two different sitting modes. We have proposed structure models for
these two adsorption sites of Mn atoms, which are in line with the corresponding
simulated STM images, and also show the system becomes magnetic after depositing
Mn atoms. On the other hand, we measure Pb c(4×4) on Si(100) at 0.3K, the result of
scanning tunneling spectroscopy (STS) shows that the bandgap of the system increases
with decreasing temperature, this indicates the c(8×4) system is not the superconductor,
because of the coverage of c(8×4) is lower than c(4×4), so the c(8×4) might be not the
superconductor either.
Sn thin film growth on Cu(111) substrate at low temperature forms the honeycomb
IV
structure “Stanene” which has research already knew is Topological insulator. In this
work, we deposited Co atoms on this system and used STM do the low-temperature
measurement. Results show that self-assembled Co atom form the Monomer, Dimer,
Trimer on the top of stanene island. With 4K STS measurement compared to Stanene,
monomer has clear peak at-0.1V, dimer and trimer also has peak at -0.3V. By the
literature already knew Co adatom on Cu(111) has spin magnetic moment. If these selfassembled
Co structures also has spin magnetic moment, this provides an ideal
experimental system with a simple and convenient measurement for future research on
the interaction between magnetic impurities and two-dimensional topological insulator.

1. He, K., Wang, Y., & Xue, Q. K. (2014). Quantum anomalous Hall effect. National Science Review, 1(1), 38-48.
2. Nadj-Perge, S., Drozdov, I. K., Li, J., Chen, H., Jeon, S., Seo, J., ... & Yazdani, A. (2014). Observation of Majorana fermions in ferromagnetic atomic chains on a superconductor. Science, 346(6209), 602-607.
3. Palacio-Morales, A., Mascot, E., Cocklin, S., Kim, H., Rachel, S., Morr, D. K., & Wiesendanger, R. (2019). Atomic-scale interface engineering of Majorana edge modes in a 2D magnet-superconductor hybrid system. Science advances, 5(7), eaav6600.
4. Ménard, G. C., Mesaros, A., Brun, C., Debontridder, F., Roditchev, D., Simon, P., & Cren, T. (2019). Isolated pairs of Majorana zero modes in a disordered superconducting lead monolayer. Nature communications, 10(1), 1-7.
5. Zhang, T., Cheng, P., Li, W. J., Sun, Y. J., Wang, G., Zhu, X. G., ... & Xue, Q. K. (2010). Superconductivity in one-atomic-layer metal films grown on Si (111). Nature Physics, 6(2), 104-108.
6. Nadj-Perge, S., Drozdov, I. K., Li, J., Chen, H., Jeon, S., Seo, J., ... & Yazdani, A. (2014). Observation of Majorana fermions in ferromagnetic atomic chains on a superconductor. Science, 346(6209), 602-607.
7. Vlaic, S., Pons, S., Zhang, T., Assouline, A., Zimmers, A., David, C., ... & Aubin, H. (2017). Superconducting parity effect across the Anderson limit. Nature communications, 8(1), 1-8.
8. Kotlyar, V. G., Utas, O. A., Utas, T. V., Bondarenko, L. V., Tupchaya, A. Y., Gruznev, D. V., ... & Saranin, A. A. (2020). Surface reconstructions in Pb/Si (100) system: 58 Composition and atomic arrangement. Surface Science, 695, 121574.
9. Kou, L., Ma, Y., Sun, Z., Heine, T., & Chen, C. (2017). Two-dimensional topological insulators: Progress and prospects. The journal of physical chemistry letters, 8(8), 1905-1919.
10. Deng, J., Xia, B., Ma, X., Chen, H., Shan, H., Zhai, X., ... & Hou, J. G. (2018). Epitaxial growth of ultraflat stanene with topological band inversion. Nature materials, 17(12), 1081-1086.
11. Diekhöner, L., Schneider, M. A., Baranov, A. N., Stepanyuk, V. S., Bruno, P., & Kern, K. (2003). Surface states of cobalt nanoislands on Cu (111). Physical review letters, 90(23), 236801
12. Pietzsch, O., Kubetzka, A., Bode, M., & Wiesendanger, R. (2004). Spin-polarized scanning tunneling spectroscopy of nanoscale cobalt islands on Cu (111). Physical Review Letters, 92(5), 057202.
13. Rastei, M. V., Heinrich, B., Limot, L., Ignatiev, P. A., Stepanyuk, V. S., Bruno, P., & Bucher, J. P. (2007). Size-dependent surface states of strained cobalt nanoislands on Cu (111). Physical review letters, 99(24), 246102.
14. Knorr, N., Schneider, M. A., Diekhöner, L., Wahl, P., & Kern, K. (2002). Kondo effect of single Co adatoms on Cu surfaces. Physical review letters, 88(9), 096804.
15. Klitzing, K. V., Dorda, G., & Pepper, M. (1980). New method for high-accuracy determination of the fine-structure constant based on quantized Hall resistance. Physical review letters, 45(6), 494.
16. Tahir, M., & Schwingenschlögl, U. (2013). Valley polarized quantum Hall effect and topological insulator phase transitions in silicene. Scientific reports,3(1), 1-5.
17. Qi, X. L., & Zhang, S. C. (2010). The quantum spin Hall effect and topological insulators. arXiv preprint arXiv:1001.1602. 59
18. Bestwick, A. J., Fox, E. J., Kou, X., Pan, L., Wang, K. L., & Goldhaber-Gordon, D. (2015). Precise quantization of the anomalous Hall effect near zero magnetic field.Physical review letters, 114(18), 187201.
19. P.J. Ford, G.A. Saunders, The Rise of the Superconductors (CRC Press, 2004), 1st Edition.
20. Compair. (1801). CompAir Oil Free Scroll Compressors. product brochure. Retrieved from https://rastgar-co.com/wp-content/uploads/2017/05/CompAir-Oil- Free-Rotary-Scroll-Compressors.pdf.
21. Charles A. Bishop, Vacuum Deposition onto Webs, Films and Foils (Second Edition), 2011.
22. An Introduction to Vacuum Pumps. January 13, 2016 by VAC AERO International
23. Chell Instruments. (2008) K-Cell Miniature Knudsen Evaporation Cell.Operators handbook.
24. FOCUS. (2017). UHV Evaporator EFM 2/3(s)/4(s). Instruction Manual. Retrieved from https://wiki.kip.uni-heidelberg.de/KIPwiki/images/c/c8/EFM3Omicron_User Manual2013.pdf.
25. Briggs, G. A. D., & Fisher, A. J. (1999). STM experiment and atomistic modelling hand in hand: individual molecules on semiconductor surfaces. Surface science reports, 33(1-2), 1-81.
26. Chen, C. J. (1993). Introduction to scanning tunneling microscopy: Second Edition. Oxford University Press on Demand.
27. Tersoff, J., & Hamann, D. R. (1985). Theory of the scanning tunneling microscope. Physical Review B, 31(2), 805.
28. Lounis, S. (2014). Theory of scanning tunneling microscopy. arXiv preprint arXiv:1404.0961. 60
29. Wiesendanger, R. (2007). Mapping spin structures on the atomic scale. Europhysics News, 38(2), 16-21.
30. Huda, Md Nurul. (2016). Epitaxial growth of lateral graphene / hexagonal boron nitride heterostructures. (Master's thesis, Aalto University, Helsinki, Finland). Retrieved from https://aaltodoc.aalto.fi/handle/123456789/23389
31. Unisoku. (2018). USM1300S He 3E. Operating Manual.
32. Hata, K., Kimura, T., Ozawa, S., & Shigekawa, H. (2000). How to fabricate a defect free Si (001) surface. Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, 18(4), 1933-1936.
33. Ramstad, A., Brocks, G., & Kelly, P. J. (1995). Theoretical study of the Si (100) surface reconstruction. Physical Review B, 51(20), 14504.
34. Weinelt, M., Kutschera, M., Schmidt, R., Orth, C., Fauster, T., & Rohlfing, M. (2005). Electronic structure and electron dynamics at Si (100). Applied Physics A, 80(5), 995-1003.
35. Kutschera, M., Weinelt, M., Rohlfing, M., & Fauster, T. (2007). Image-potentialinduced surface state at Si (100). Applied Physics A, 88(3), 519-526.
36. Guo, Y., Zhang, Y. F., Bao, X. Y., Han, T. Z., Tang, Z., Zhang, L. X., ... & Xue, Q. K. (2004). Superconductivity modulated by quantum size effects. Science, 306(5703), 1915-1917.
37. Şahin, H., Cahangirov, S., Topsakal, M., Bekaroglu, E., Akturk, E., Senger, R. T., & Ciraci, S. (2009). Monolayer honeycomb structures of group-IV elements and IIIV binary compounds: First-principles calculations. Physical Review B, 80(15), 155453.