本研究透過自旋極化穿隧掃描式顯微鏡(Spin-Polarized Scanning Tunneling Microscopy, SP-STM)量測在單原子層Mn/Ag(111)中120° Néel反鐵磁結構(120° Antiferromagnetic Néel Structure)以及其行為，並且利用SP-STM模擬來解析自旋結構以及方向，進一步探討其中物理性質。在模擬上透過簡單的穿隧模型與針尖至樣品波函數自旋態修正的自旋閥模型，再加上程式上的模擬就可以簡單的模擬出在特定自旋結構下SP-STM量測到的表面原子圖像。實驗上量測到Mn原子以(1×1)成長在Ag(111)基板上，並且在自旋極化針尖的量測下可以得到(√3×√3)磁性結構，且SP-STM模擬與實驗結果相當吻合，並且透過模擬可以解出實際上量測到的樣品自旋方向以及對應針尖的自旋極化方向，最後透過這系列的研究方法我們還可以解析出磁疇壁間每個原子自旋的方向及變化行為。
緊接著將Mn成長至Bi/Ag(111)系統中，在這個系統中Bi在高溫下成長，且根據Bi鍍量的多寡會形成(√3×√3)R30° BiAg2合金(Alloying)以及(p×√3)的去合金(Dealloying)態，可惜的是Mn無法再有強自旋軌道效應的BiAg2合金上形成二維結構，但意外的是在不平整的去合金Bi表面上形成了平整的(2×2)蜂巢狀結構，透過研究去合金Bi的原子結構以及蜂巢狀結構島嶼周遭原子結構，我們猜測Mn會影響到Bi原子間的鍵結，導致Bi從去合金態轉變回BiAg3的(2×2)合金結構，且Mn在BiAg3上成長為蜂巢狀結構。

In this study, we have resolved the 120° Néel structure in real space by spin-polarized scanning tunneling microscopy (SP-STM) at monolayer Mn on Ag (111) , a and discuss the results in terms of various Néel spin textures by SP-STM simulations. In the simulations, a simple one-dimensional tunneling model combined with spin-valve model incorporating the tip-sample wavefunction spin states is utilized to simulate the surface spin structures observed in SP-STM measurements. Experimental results shows that monolayer Mn is not only pseudomorphically growing on Ag(111) but also shows the √3×√3 Néel spin structure within spin-polarized tip measurement. Comparing experiments with simulation results, we can reproduce the spin textures in different magnetic domains and understand the behavior of domain wall.
Next, Mn is grown on the Bi/Ag(111) system. where Bi is grown at high temperatures. Depending on the Bi coverage, (√3×√3)R30° BiAg2 alloying phase and dealloying phase are formed. Unfortunately, Mn cannot form a two-dimensional structure on the BiAg2 alloy phase. However, unexpectedly, Mn forms a flat (2×2) honeycomb structure on the structure reconstruction surface of the dealloying Bi. By studying the STM measurement atomic structure of the dealloying Bi , and the surrounding (√3×√3) BiAg2 alloying atomic of the honeycomb Mn islands, we speculate that Mn affects the bonding between Bi atoms, causing a transition from the Bi dealloying state back to the (2×2) BiAg3 alloy structure. So we can observe of the surface honeycomb Mn structure on top of the BiAg3 alloy.

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