先前的研究已經利用第一原理計算方法預測三五族元素在單一雙分子層結構並探討其電子結構、拓撲性質與可用性。本次研究中，利用相同方法改變三族鉍化物(IIIA-Bi)層數，並探討材料結構及拓撲性質。之後也更進一步探討材料成長於矽(111)基板後的拓撲特性。
　　本研究的目的是發現可被利用於室溫且具有拓撲特性的新穎材料。利用第一原理電子結構計算模擬三族鉍化物(IIIA-Bi)材料結構在少數雙分子層的特性，並同時探討應變的影響。而且我們也利用氫原子鍵結在化合物薄膜上。研究結果中發現二層分子層的鉍化鋁、鉍化鎵和鉍化銦，在範圍(-6%至6%)的應變下大部分都為拓撲絕緣體。另外鉍化硼與鉍化鉈也在應變下轉變成具非平庸(nontrivial)特性的材料。在研究中也發現，與氫鍵結後二層的鉍化鎵及鉍化銦具有大於100豪電子伏特(meV)的能隙。二層的鉍化鎵和鉍化銦與矽基板結合的結果中，發現將鉍化鎵與基板結合後依然保持具非平庸(nontrivial)性質且能隙大小為121豪電子伏特(meV)。經過與氫鍵結跟與矽基板鍵結後發現皆可維持材料拓撲特性，之後可將三族鉍化物薄膜與適當的基板鍵結。

Previous studies have explored the electronic and topological properties of group III-V in buckled honeycombs and revealed that this group of materials exhibits nontrivial insulating phase. In this study, we investigated the thickness dependence of III-Bi thin-films and their growths on Si(111) using first-principles electronic structure calculations.
The aim of this study is to find new novel materials harboring nontrivial topological phase that could be used for future room-temperature applications. We used first-principles calculations to simulate and study the growth of ultrathin films of compounds consisting of group III (B, Al, In, Ga, and Tl) with Bi upon hydrogenation as well as those on Si(111) substrate. Furthermore, using two-sided hydrogenation, we found that two bilayers (BLs) of AlBi, InBi, and GaBi harbor a nontrivial topological phase over a wide range (-6% ~ 6%) of strain, while BBi and TlBi can still be driven into the nontrivial phase by applying strain. A large band gap is identified in hydrogenated 2 BL films of InBi and GaBi. 2 BL films of GaBi and InBi surface possess nontrivial phases and a band gap as large as 121 meV was found in the case of 2 BL films of GaBi. Since the nontrivial phase is maintained upon hydrogenation and on Si(111) substrate, this suggests that these III-Bi thin films are possible to be grown in suitable substrates.

論文審定書 i
摘要 ii
Abstract iii
目錄 iv
圖次 v
表次 vii
1.導論 １
2.理論與計算方法 ３
2.1拓撲學背景 ３
2.2 拓撲不變量Z2(topological invariant) ３
2.3計算方法 ４
3.雙分子層薄膜結構之三族鉍化合物結果 ５
3.1雙分子層薄膜結構介紹 ５
3.2三族鉍化物(III-Bi)的應變與拓撲相變 ８
3.2.1純三族鉍化物薄膜 ８
3.2.2三族鉍化物薄膜加氫鈍化 １３
4. 雙分子層薄膜三族鉍化物在矽基板 １９
4.1矽基板結構介紹 １９
4.2三族鉍化物生長在矽基板上之結果與討論 ２１
5.結論 ２４
6.參考文獻 ２５

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