我們利用第一原理電子結構計算預測新一類的二維 (2D) 拓撲絕緣體 (TIs)基於氫化的砷蜂巢結構 (hydrogenated arsenic honeycomb structures) 。單一雙分子層 (bilayer) 的砷蜂巢結構在平衡態時為絕緣體。而在應力的作用下會從一般態轉變成拓撲態。接著討論雙面吸附氫原子後，結構會從皺褶結構變成平面結構。根據我們的宇稱 (parity) 分析，其平衡態為拓撲態。最後，考慮單面吸附氫原子並藉由辨識邊界態能帶和計算 Z2 不變量得知在平衡態時保持拓撲態。

We use first-principles electronic structure calculations to predict a new class of two-dimensional (2D) topological insulators (TIs) in hydrogenated arsenic honeycomb structures. Single bilayer of arsenic honeycomb structures had been identified as a trivial insulator and it transforms into a non-trivial insulator under strain. The buckled structures become a nearly planar honeycomb structure after hydrogen adsorptions on two sides. Based on our parity analysis, it is in non-trivial phase at structural equilibrium state. Finally, we discuss the one-sidedly hydrogenated arsenic honeycomb structures. It is also in a non-trivial phase on equilibrium state by using identified topologically protected edge state and Z_2 invariant.

論文審定書 i
中文摘要 ii
Abstract iii
目錄 iv
圖次 vi
表次 xi
1. 緒論： 1
2. 理論與方法： 3
2.1 拓撲絕緣體 3
2.2 計算方法 6
3. 結果與討論：砷(111)面 7
3.1 砷的原子結構 7
3.2 砷(111)面薄膜的結構穩定性 9
3.3 砷(111)面的能帶結構 11
3.4 砷(111)面的絕熱轉換分析 15
3.5 砷(111)面的宇稱分析 18
4. 結果與討論：砷(111)面單面吸附氫 20
4.1 砷(111)面單面吸附氫原子的結構穩定性 20
4.2 砷(111)面單面吸附氫原子的能帶結構 22
4.3 砷(111)面單面吸附氫原子的絕熱轉換分析 25
5. 結果與討論：砷(111)面雙面吸附氫 30
5.1 砷(111)面雙面吸附氫原子的結構穩定性 30
5.2 砷(111)面雙面吸附氫原子的能帶結構 32
5.3 砷(111)面雙面吸附氫原子的絕熱轉換分析 35
5.4 砷(111)面雙面吸附氫原子的宇稱分析 37
6. 結果與討論： 38
參考文獻 42

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