簡易檢索 / 詳目顯示
| 研究生： |
黃勢棠 Huang, Shih-Tang |
|---|---|
| 論文名稱： |
單層錫烯成長於鐵磁性鈷奈米島 Monolayer Stanene Grown on Ferromagnetic Cobalt Nanoislands |
| 指導教授： |
徐斌睿
Hsu, Pin-Jui |
| 口試委員: |
林登松
Lin, Deng-Sung 王柏堯 Wang, Bo-Yao |
| 學位類別： |
碩士 Master |
| 系所名稱： |
理學院 - 物理學系 Department of Physics |
| 論文出版年： | 2021 |
| 畢業學年度： | 109 |
| 語文別： | 中文 |
| 論文頁數： | 55 |
| 中文關鍵詞： | 表面物理 、自旋極化掃描穿隧顯微鏡 、二維拓樸絕緣體 、單層錫烯 、鐵磁性鈷銅奈米島嶼 、磁性二維拓樸絕緣體 |
| 外文關鍵詞： | Surface science, Spin-polarized scanning tunneling microscopy, Two-dimensional topological insulator, Monolayer stanene, Co nanoislands/Cu(111), Magnetic two-dimensional topological insulator |
| 相關次數： | 點閱：4 下載：0 |
| 分享至: |
| 查詢本校圖書館目錄 查詢臺灣博碩士論文知識加值系統 勘誤回報 |
二維拓樸絕緣體，包含量子自旋霍爾效應與量子反常霍爾效應，因其能帶結構特殊的拓樸性質，被期許可應用於低功率、低失真的電訊號傳輸，以及自旋電子學。根據理論的預測，量子反常霍爾效應可藉由破壞拓樸絕緣體本身的時間反演對稱性的方式被實現。於近年的實驗中，量子反常霍爾效應於參雜了磁性雜質的三維拓樸絕緣體被觀察到，而到目前為止並沒有關於磁性二維拓樸絕緣體的實驗。
本實驗將具有鐵磁性、兩層原子層的奈米鈷島嶼製備於Cu(111)基板上，並嘗試於鈷島嶼上成長有較大拓樸能隙(0.3eV)的二維拓樸絕緣體stanene。以期透過將二維拓樸絕緣體成長於鐵磁性的奈米島嶼之上的方式，製備具有磁性的二維拓樸絕緣體，嘗試實現量子反常霍爾效應。實驗中我們會以掃描穿隧顯微鏡與掃描穿隧能譜量測樣品原子尺度的形貌、電性與磁性結構。
我們透過分子束磊晶法成功地將stanene製備於鐵磁性的鈷奈米島嶼上。在77 K與4 K的量測中，我們發現在成長於鈷島嶼上的stanene之掃描穿隧能譜於約0.1 V處存在一個峰值，並且於費米能階附近(-0.2 V~0.6 V)的電導圖中觀察到表面電子的散射波紋。這些特徵都不會於單純stanene/Cu(111)系統中被觀察到，很可能是stanene本身的時間反演對稱性受到磁性島嶼的破壞而導致，這為實現磁性二維拓樸絕緣體提供一條明確的提示。
Two-dimensional topological insulators (TIs), where the quantum spin Hall effect and the quantum anomalous Hall effect emerge, are promising to be applied to the low power and the low distortion electrical signal transmission in the spintronics due to the extraordinary topological properties of the band structures. According to the theoretical prediction, the quantum anomalous Hall effect can be realized by breaking the time reversal symmetry in TIs. In recent studies, the quantum anomalous Hall effect has been measured in 3D-TIs doped magnetic impurities at low temperature. But, the experiment of magnetic 2D-TIs has not been reported yet.
We attempt to fabricate magnetic 2D-TI by growing 2D-TI stanene, which has large topological band gap (~0.3 eV) on ferromagnetic 2 ML Cobalt nanoislands on the Cu(111) substrate to realize a system where the quantum anomalous Hall effect could be present. In our experiments, we utilize scanning tunneling microscope and scanning tunneling spectroscopy to measure the atomic and electronic properties of the sample.
We have successfully fabricated the stanene on the ferromagnetic Cobalt nanoislands by molecular beam epitaxy. At 77 K and 4 K measurements, the peak at approximately 0.1 eV in STS spectrum of stanene/Co/Cu(111) can be observed. We also found scatterings of surface electron on the stanene/Co/Cu(111) from the dl/dU mapping near the Fermi level (-0.2V~0.6V). These features do not exist in the stanene/Cu(111) system. It implies that the time reversal symmetry on stanene might be broken by the magnetism of Cobalt nanoisland and offers a hint for realizing magnetic 2D-TIs.
[1] Y. Ren, Z. Qiao, and Q. Niu, Reports on Progress in Physics 79, 066501 (2016).
[2] L. Kou, Y. Ma, Z. Sun, T. Heine, and C. Chen, The Journal of Physical Chemistry Letters 8, 1905 (2017).
[3] F. D. M. Haldane, Physical Review Letters 61, 2015 (1988).
[4] C.-X. Liu, S.-C. Zhang, and X.-L. Qi, arXiv preprint arXiv:1508.07106 (2015).
[5] C. L. Kane and E. J. Mele, Physical Review Letters 95, 226801 (2005).
[6] X.-L. Qi and S.-C. Zhang, Physics Today 63, 33 (2010).
[7] D. Tong, arXiv preprint arXiv:1606.06687 (2016).
[8] H. Weng, X. Dai, and Z. Fang, arXiv preprint arXiv:1509.05507 (2015).
[9] M. Z. Hasan and C. L. Kane, Reviews of Modern Physics 82, 3045 (2010).
[10] J. Maciejko, T. L. Hughes, and S.-C. Zhang, Annual Review of Condensed Matter Physics 2, 31 (2011).
[11] F. Ortmann, S. Roche, and S. O. Valenzuela, Topological Insulators: Fundamentals and Perspectives (John Wiley & Sons, 2015).
[12] R. M. Kaufmann, D. Li, and B. Wehefritz-Kaufmann, Reviews in Mathematical Physics 28, 1630003 (2016).
[13] X. Kou et al., Nature Communications 6, 1 (2015).
[14] Y. Xu, B. Yan, H.-J. Zhang, J. Wang, G. Xu, P. Tang, W. Duan, and S.-C. Zhang, Physical Review Letters 111, 136804 (2013).
[15] F.-F. Zhu, W.-J. Chen, Y. Xu, C.-L. Gao, D.-D. Guan, C.-H. Liu, D. Qian, S.-C. Zhang, and J.-F. Jia, Nature Materials 14, 1020 (2015).
[16] J. Deng et al., Nature Materials 17, 1081 (2018).
[17] L. Diekhöner, M. A. Schneider, A. N. Baranov, V. S. Stepanyuk, P. Bruno, and K. Kern, Physical Review Letters 90, 236801 (2003).
[18] O. Pietzsch, A. Kubetzka, M. Bode, and R. Wiesendanger, Physical Review Letters 92, 057202 (2004).
[19] M. V. Rastei, B. Heinrich, L. Limot, P. A. Ignatiev, V. S. Stepanyuk, P. Bruno, and J. P. Bucher, Physical Review Letters 99, 246102 (2007).
[20] 伍秀菁、汪若文、林美吟編輯，真空技術與應用(國研院儀科中心，民90)
[21] S. Gasiorowicz, Quantum Physics (John Wiley & Sons, 2007).
[22] J. Chen, Introduction to Scanning Tunneling Microscopy (Oxford University Press (S3), 2007), Hardback, 2nd Revised edn.
[23] J. Tersoff and D. R. Hamann, Physical Review Letters 50, 1998 (1983).
[24] B. E. Murphy, Trinity College Dublin, 2014.
[25] R. Wiesendanger, Europhysics News 38, 16 (2007).