本研究旨在探討磁性金屬與拓撲絕緣體（TIs）異質結構薄膜的物理性質，特別聚焦於Cr₂Te₃/Sb₂Te₃ 異質結構。我們綜合運用先進的掃描式穿隧顯微鏡（STM）與掃描式穿隧能譜（STS）技術，並輔以角分辨光電子能譜（ARPES）量測，對樣品的表面原子結構與電子能譜進行了詳細分析。實驗結果顯示Cr2Te3/ Sb2Te3異質結構薄膜表面的原子排列呈現為扭曲的六角型結構（distorted hexagonal structure）。
透過比對純Cr2Te3與Cr2Te3/ Sb2Te3異質結構薄膜的 STS 和 ARPES 數據，我們發現在Cr2Te3/ Sb2Te3異質結構的能譜中，於費米面下-0.1eV附近多出一個額外的電子態訊號。此訊號在角分辨光電子能譜（ARPES）中表現為一條水平的非色散能帶（non-dispersive band or flat band），而在掃描式穿隧光譜（STS）中則對應為一個明顯的態密度峰值（peak structure）。
此非色散能帶的發現，明確指出了特殊束縛態的存在，為未來深入研究Cr2Te3/ Sb2Te3異質結構薄膜的電學或磁學特性提供了重要的實驗依據與物理圖像。

This study investigates the physical properties of heterostructure thin films composed of magnetic metals and topological insulators (TIs), with a specific focus on the Cr₂Te₃/Sb₂Te₃ heterostructure system. We systematically employed advanced scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS) techniques, complemented by angle-resolved photoemission spectroscopy (ARPES) measurements, to conduct a detailed analysis of the samples' surface atomic structure and local electronic spectra. By comparing the STS and ARPES data from both pure Cr₂Te₃ and the Cr₂Te₃/Sb₂Te₃ heterostructure films, we identified an additional electronic state signal within the heterostructure's spectrum located approximately -0.1 eV below the Fermi level (EF). This signal manifests as a horizontal, non-dispersive band (or flat band) in the ARPES data, and corresponds to a pronounced density of states (DOS) peak structure in the STS spectra. The discovery of this non-dispersive band clearly indicates the presence of specific localized or confined states, providing crucial experimental evidence and a foundational physical picture for future in-depth investigations into the electrical and magnetic properties of Cr₂Te₃/Sb₂Te₃ heterostructure films.

[1]張泰榕. (2017) 拓樸材料與拓樸能帶理論. 物理雙月刊.
[2]叶飞 and 苏刚, "拓扑绝缘体及其研究进展," 物理, vol. 39, no. 08, pp. 564–569, 2010. [Online]. Available: https://wuli.iphy.ac.cn/cn/article/id/31779.
[3]C. Kittel, 固体物理导论. 化学工业出版社, 2005.
[4]游至仕 and 王奕誠, "能帶拓樸：從厄米走向非厄米," 物理雙月刊, 2023.
[5]張泰榕;曾郁欽. (2016) 拓樸理論 提供物質新觀點. 物理月刊.
[6]Y. Tokura, K. Yasuda, and A. Tsukazaki, "Magnetic topological insulators," Nature Reviews Physics, vol. 1, no. 2, pp. 126–143, 2019, doi: 10.1038/s42254-018-0011-5.
[7]Y. Zhong et al., "From Stoner to local moment magnetism in atomically thin Cr2Te3," Nature Communications, vol. 14, no. 1, p. 5340, 2023.
[8]鹏. 程, 曦. 陈, 童. 张, 薛其坤, 珂. 何, and 马旭村, "拓扑绝缘体表面态的STM研究," 物理, vol. 40, no. 07, pp. 449–453, 2011. [Online]. Available: https://wuli.iphy.ac.cn/cn/article/id/32042.
[9]C. Y. R. Wei, " Research advances of topological quantum materials," Chinese Journal of Nature, 2019, doi: 10.3969/j.issn.0253-9608.2019.05.005.
[10]T. Das, "A Pedagogic Review on Designing Model Topological Insulators," Indian Institute of Science, 2016.
[11]Z.-M. Zhang, W.-H. Zhang, and Y.-S. Fu, "Scanning tunneling microscopy study on two-dimensional topological insulators," Acta Physica Sinica, vol. 68, no. 22, pp. 226801–1–226801–19, 2019, doi: 10.7498/aps.68.20191631.
[12]吳自勤, 薄膜生長, 2 ed. 科學出版社, 2021.
[13]C. Pauly, Strong and Weak Topology Probed by Surface Science: Topological Insulator Properties of Phase Change Alloys and Heavy Metal Grap (Matwerk). Spektrum Akademischer Verlag Gmbh, 2015.
[14]A. Bansil, H. Lin, and T. Das, "Colloquium: Topological band theory," Reviews of Modern Physics, vol. 88, no. 2, 2016, doi: 10.1103/RevModPhys.88.021004.
[15]H. Chen, H. Nassar, and G. L. Huang, "A study of topological effects in 1D and 2D mechanical lattices," Journal of the Mechanics and Physics of Solids, vol. 117, pp. 22–36, 2018/08/01/ 2018, doi: https://doi.org/10.1016/j.jmps.2018.04.013.
[16]曹全喜, 雷天民, 黃雲霞, and 李桂芳, 固體物理基礎. 西安電子科技大學出版社, 2008.
[17]黃翊東, 固態物理基礎. 清華大學出版社, 2022.
[18]S. Datta, Electronic Transport in Mesoscopic Systems. Cambridge University Press, 1997.
[19]L. Bányai, A Compendium of Solid State Theory. Springer Cham, 2020.
[20]牛谦, 高阳, and 肖聪, "半经典响应理论," 物理, vol. 53, no. 7, pp. 460–471, 2024, doi: 10.7693/wl20240704.
[21]LibreTexts. Density of States [Online] Available: https://eng.libretexts.org/Bookshelves/Materials_Science/Supplemental_Modules_(Materials_Science)/Electronic_Properties/Density_of_States
[22]B. Spears. Semiconductor Physics: Density of States [Online] Available: https://britneyspears.ac/physics/dos/dos.htm
[23]"Materials Data on Sb2Te3 by Materials Project," 2020, doi: 10.17188/1188507.
[24]H. Zhang, C.-X. Liu, X.-L. Qi, X. Dai, Z. Fang, and S.-C. Zhang, "Topological insulators in Bi2Se3, Bi2Te3 and Sb2Te3 with a single Dirac cone on the surface," Nature Physics, vol. 5, no. 6, pp. 438–442, 2009/06/01 2009, doi: 10.1038/nphys1270.
[25]C. Li, O. van ‘t Erve, Y. Li, L. Li, and B. Jonker, "Electrical detection of the helical spin texture in a p-type topological insulator Sb2Te3," Scientific reports, vol. 6, no. 1, p. 29533, 2016.
[26]S. Zhu et al., "Ultrafast electron dynamics at the Dirac node of the topological insulator Sb2Te3," Sci Rep, vol. 5, p. 13213, Aug 21 2015, doi: 10.1038/srep13213.
[27]P. o. S. N. © Springer Nature Switzerland AG. "Chromium Telluride (Cr2Te3)." (accessed.
[28]B. LBNL Materials Project; Lawrence Berkeley National Laboratory (LBNL), CA (United States), "Materials Data on Cr2Te3 by Materials Project," 2020, doi: https://doi.org/10.17188/1201718.
[29]紀承濬, "Sb2Te3-Cr2Te3異質結構薄膜製程和費米能階調控之研究," 碩士, 物理學系, 國立成功大學, 台南市, 2024. [Online]. Available: https://hdl.handle.net/11296/y9qn6u
[30]H. Huang et al., "Controllable phase transition of two-dimensional ferromagnetic chromium telluride thin films grown by molecular beam epitaxy," Quantum Frontiers, vol. 2, no. 1, p. 12, 2023.
[31]T. Yilmaz et al., "Emergent flat band electronic structure in a VSe2/Bi2Se3 heterostructure," Communications Materials, vol. 2, no. 1, p. 11, 2021.
[32]侯伯元, 雲國宏, and 楊戰營, 路徑積分與量子物理導引︰現代高等量子力學初步 (現代物理基礎叢書). 科學出版社, 2008.
[33]文小剛, 量子多體理論：從聲子的起源到光子和電子的起源. 高等教育出版社, 2004.
[34]K. W. Hipps and U. Mazur, "Inelastic Electron Tunneling: An Alternative Molecular Spectroscopy " The Journal of Physical Chemistry, vol. 97, issue 30, pp. 7803-7814, 1993, doi: 10.1021/j100132a004.
[35]C. J. Chen, Introduction to Scanning Tunneling Microscopy. Oxford University Press, 1993.
[36]S. Tang et al., "Quantum spin Hall state in monolayer 1T'-WTe2," Nature Physics, vol. 13, no. 7, pp. 683–687, 2017.
[37]F. Yang et al., "Spatial and energy distribution of topological edge states in single Bi (111) bilayer," Physical review letters, vol. 109, no. 1, p. 016801, 2012.
[38]R. Dombrowski, C. Steinebach, C. Wittneven, M. Morgenstern, and R. Wiesendanger, "Tip-induced band bending by scanning tunneling spectroscopy of the states of the tip-induced quantum dot on InAs (110)," Physical Review B, vol. 59, no. 12, p. 8043, 1999.
[39]R. Wiesendanger. Tip induced quantum dot [Online] Available: https://www.physik.uni-hamburg.de/en/inf/ag-wiesendanger/forschung/research-archive/semiconductors/tip-induced.html
[40]M. Morgenstern, A. Georgi, C. Straßer, C. R. Ast, S. Becker, and M. Liebmann, "Scanning tunneling microscopy of two-dimensional semiconductors: Spin properties and disorder," Physica E: Low-dimensional Systems and Nanostructures, vol. 44, no. 9, pp. 1795–1814, 2012, doi: 10.1016/j.physe.2012.06.006.
[41]S. Yoshida, J. Kikuchi, Y. Kanitani, O. Takeuchi, H. Oigawa, and H. Shigekawa, "Tip-induced band bending and its effect on local barrier height measurement studied by light-modulated scanning tunneling spectroscopy," e-Journal of Surface Science and Nanotechnology, vol. 4, pp. 192–196, 2006, doi: 10.1380/ejssnt.2006.192.
[42]A. D. Gottlieb and L. Wesoloski, "Bardeen’s tunnelling theory as applied to scanning tunnelling microscopy: a technical guide to the traditional interpretation," Nanotechnology, vol. 17, no. 8, p. R57, 2006/03/15 2006, doi: 10.1088/0957-4484/17/8/R01.
[43]C. Hellenthal, R. Heimbuch, K. Sotthewes, E. S. Kooij, and H. J. W. Zandvliet, "Determining the local density of states in the constant current STM mode," Physical Review B, vol. 88, no. 3, 2013, doi: 10.1103/PhysRevB.88.035425.
[44]J.-X. Yin, S. H. Pan, and M. Zahid Hasan, "Probing topological quantum matter with scanning tunnelling microscopy," Nature Reviews Physics, vol. 3, no. 4, pp. 249–263, 2021.
[45]P. Hansma, Tunneling Spectroscopy: Capabilities, Applications, And New Techniques by Paul Hansma. Springer, 1982.
[46]彭海琳, 拓樸絕緣體:基礎及新興應用. 科學出版社, 2020.
[47]C. Hess, Quantum Materials: Experiments and Theory. Forschungszentrum Jülich GmbH,Institute for Advanced Simulation, 2016.
[48]M. Assig, M. Etzkorn, A. Enders, W. Stiepany, C. R. Ast, and K. Kern, "A 10 mK scanning tunneling microscope operating in ultra high vacuum and high magnetic fields," Review of Scientific Instruments, vol. 84, no. 3, 2013.
[49]C. Liu and X.-R. Liu, "Angle resolved photoemission spectroscopy studies on three dimensional strong topological insulators and magnetic topological insulators," Acta Physica Sinica, vol. 68, no. 22, pp. 227901–1–227901–44, 2019, doi: 10.7498/aps.68.20191450.
[50]A. Damascelli, Z. Hussain, and Z.-X. Shen, "Angle-resolved photoemission studies of the cuprate superconductors," Reviews of modern physics, vol. 75, no. 2, p. 473, 2003.