| 研究生: |
施佳彤 Shi, Jia-Tong |
|---|---|
| 論文名稱: |
應變石墨烯之贋磁傳輸模擬 Pseudomagnetotransport simulations for strained graphene |
| 指導教授: |
劉明豪
Liu, Ming-Hao |
| 學位類別: |
碩士 Master |
| 系所名稱: |
理學院 - 物理學系 Department of Physics |
| 論文出版年: | 2024 |
| 畢業學年度: | 112 |
| 語文別: | 中文 |
| 論文頁數: | 44 |
| 中文關鍵詞: | 石墨烯 、應變 、贋磁場 、量子傳輸模擬 |
| 外文關鍵詞: | graphene, strain, pseudo-magnetic field, quantum transport simulations |
| 相關次數: | 點閱:82 下載:60 |
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石墨烯因其單層原子的極薄特性,極易受到外部施加的機械變形的影響。 因此,長期以來,人們一直在理論和實驗上對應變石墨烯進行研究。 在所有有趣的預測中,石墨烯中的贋磁場在適當設計的應變場下產生的效應相當於石墨烯在10T量級的強外加磁場下產生的效應,可能是討論最多的話題之 一。 儘管在實驗中已經觀察到石墨烯氣泡和波紋中由於強贋磁場而產生的贋蘭道能階特徵,但在應變石墨烯中顯示強贋磁場的傳輸實驗到目前為止還沒有。 為了給未來可能在應變石墨烯上進行的贋磁傳輸實驗提供可靠的模擬,我們在這裡對三軸應變石墨烯進行了量子傳輸模擬,重點研究了弱贋磁場下的橫向磁聚焦(TMF )。 我們特別比較了應變石墨烯中贋磁場和石墨烯中外部磁場引起的TMF譜。 為了模擬實驗尺寸的石墨烯樣品,我們也對應變緊束縛模型與縮放因子的結合對贋蘭道能階的依賴進行了數值研究。 原始石墨烯中的磁運輸和三軸應變石墨烯中的贋磁輸運的輸運特徵確實相似,但可以識別出贋磁場不均勻性可能導致的顯著差異。
Graphene is highly susceptible to externally applied mechanical deformation due to its atomic thinness. As such, strained graphene has long been studied both theoretically and experimentally. Among all interesting predictions, the pseudo-magnetic field in graphene under properly designed strain fields, giving rise to effects equivalent to graphene under a strong external magnetic field on the order of 10 Tesla , is perhaps one of the most intensively discussed topics. Despite the fact that signatures of pseudo-Landau levels due to strong pseudo-magnetic fields in graphene bubbles and ripples have been experimentally observed, transport experiments showing strong pseudo-magnetic fields in strained graphene have so far been missing. To provide reliable guides to possible future pseudo-magnetotransport experiments on strained graphene, here we perform quantum transport simulations for triaxially strained graphene, focusing on transverse magnetic focusing (TMF) in the weak pseudo-magnetic field regime. In particular, we compare the TMF spectra due to pseudo-magnetic fields in strained graphene and external magnetic fields in pristine graphene. In order to simulate experimentally sized graphene samples, we also provide a numerical study on the dependence of the pseudo-Landau levels on the scaling factor of the scalable tight-binding model. Transport features of magnetotransport in pristine graphene and pseudo-magnetotransport in triaxially strained graphene are found to be indeed similar, but significant differences possibly arising from the nonuniformity of the pseudo-magnetic field can be identified.
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