拓樸絕緣體特殊的能帶結構導致此種材料在內部絕緣而在邊緣或表面導電，而若是將將磁性元素引入到Sb2Te3等三維拓撲絕緣體中，則會破壞時間反衍對稱性 (time reversal symmetry)，使其具有能實現量子異常霍爾效應 (Quantum Anomalous Hall Effect, QAHE) 的潛力。而MnSb2Te4即為一種被預測為本質性磁性拓樸絕緣體的材料。
本實驗以分子束磊晶系統(Molecular beam epitaxy，MBE) 透過調控分壓比以及成長溫度以及變更退火方式得到晶向結構穩定的磁性拓樸絕緣體MnSb2Te4薄膜，再改變不同Mn的分壓比成長MnSb2Te4薄膜，並進行物理性質的分析。先以反射高能電子繞射儀(Reflection high-energy electron diffraction，RHEED)確認薄膜品質，之後使用X光繞射儀(X-ray diffraction, XRD)進行晶格結構的分析，透過調控Mn的分壓比觀察樣品結構的變化。使用原子力顯微鏡(Atomic force microscope, AFM)觀察薄膜表面因為溫度變化及不同Mn分壓比所造成的表面形貌及表面平整度變化。利用穿透式電子顯微鏡(Transmission electron microscope，TEM)確認薄膜為層狀結構以及樣品厚度，再使用能量散佈分析儀(Energy dispersive spectrometer, EDS)分析薄膜的化學成分，確認樣品的元素比例。藉由X射線光電子能譜儀(X-ray photoelectron spectrometer, XPS)及拉曼光譜儀(Raman spectrometer)確認薄膜的元素和聲子的光學震動模式。利用超導量子干涉儀(Superconducting Quantum Interference Device, SQUID)量測不同Mn分壓比下成長的薄膜整體磁性行為。最後使用角解析光電子能譜(Angle resolved photoemission spectroscopy, ARPES)量測MnSb2Te4薄膜的能帶結構，由導帶與價帶間的能隙發現表面態存在，證明MnSb2Te4為拓樸絕緣體。

In this study, MnSb2Te4 magnetic topological insulator thin films were grown on the sapphire (0001) substrate with molecular beam epitaxy (MBE) system. By controlling the growth temperature and flux ratio, the high quality and single-phase structure of MnSb2Te4 thin films are performed. Using X-ray diffraction (XRD), the single crystal along c-axis direction in thin films is confirmed and the structure change with adjusting the Mn flux ratio. The elements and the optical vibration modes of thin films are identified by X-ray photoelectron spectrometer (XPS) / Hard X-ray Photoelectron Spectroscopy (HAXPES) and Raman spectra. The layered structure and thickness of thin films are characterized with X-ray reflectometry (XRR) and transmission electron microscope (TEM), and chemical composition is analyzed by energy dispersive spectrometer (EDS), which verifies the stoichiometry of thin films. The surface flatness of thin films is affected by the different growth temperature and Mn flux ratio from the observation of atomic force microscope (AFM). To observe the Mn Sb anti-site defects through scanning tunneling microscope (STM). From angle resolved photoemission spectroscopy (ARPES) results, the surface state can be observed, confirming that the MnSb2Te4 films are topological insulators.
The magnetic behavior of the thin films was confirmed with Superconducting quantum interference device (SQUID).

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