跳到主要內容

簡易檢索 / 詳目顯示

研究生: 鄭潤灃
Jun-Feng Cheng
論文名稱: 古典力學非厄米特系統石墨烯結構之拓樸邊緣態研究
Study on the Non-Hermitian Topological Edge States in Classical Mechanical Graphene Structure Systems
指導教授: 欒丕綱
口試委員:
學位類別: 碩士
Master
系所名稱: 理學院 - 光電科學與工程學系
Department of Optics and Photonics
論文出版年: 2025
畢業學年度: 113
語文別: 中文
論文頁數: 56
中文關鍵詞: 石墨烯拓樸極化
相關次數: 點閱:12下載:0
分享至:
查詢本校圖書館目錄 查詢臺灣博碩士論文知識加值系統 勘誤回報
  • 本論文主要研究古典力學石墨烯結構的晶格在非厄米特系統的狀況下,其邊緣態所發生的變化。為了實現非厄米特系統,我們將阻尼考慮進連接晶格的彈簧裡,以此來得到遞迴矩陣的關係式。
    首先我們用推導出的遞迴矩陣,模擬出了在無阻尼之下,幾種不同晶格形狀的頻譜圖以及邊緣態。接著分別討論加入阻尼後的系統,以及具有PT對稱 (PT symmertry) 的阻尼系統,發現在給予特定大小範圍的阻尼後,特徵頻率的實部與虛部兩者之間的數量級相同。在此範圍下調整阻尼的大小,觀察到邊緣態被虛部頻譜擾動產生而變化,虛部頻譜輕則影響邊緣態的衰減速度;重則使邊緣態不再衰減而成為簡併態。


    This thesis primarily investigates the behavior of edge states in the lattice structure of classical mechanical graphene under non-Hermitian systems. To realize a non-Hermitian system, damping is incorporated into the springs connecting the lattice, allowing us to derive a recursive matrix relation.
    First, using the derived recursive matrix, we simulate the spectral diagrams and edge states for various lattice geometries without damping. We then discuss both the system with damping and the system with PT symmetry (parity-time symmetry) damping. It is observed that when the damping is set within a specific range, the real and imaginary parts of the eigenfrequencies become comparable in magnitude. By tuning the damping strength within this range, we observe that the edge states are modified due to perturbations from the imaginary part of the spectrum: in milder cases, the imaginary part affects the decay rate of the edge states; in more severe cases, the edge states no longer decay and instead become degenerate states.

    摘要 i Abstract ii 誌謝 iii 目錄 iv 圖目錄 v 一、緒論 1 1-1 簡介 1 1-2 拓樸物理的基本概念 1 1-3 量子霍爾效應 4 1-4 拓樸性質在古典力學系統中的發展 5 二、文獻探討與理論 8 2-1 貝里相 ( Berry phase ) 8 2-2 陳數和威爾森迴圈 9 2-3 石墨烯晶格的邊緣態 11 2-3-1 zigzag晶格的簡併態 ( bulk state ) 13 2-3-2 zigzag晶格的邊緣態 14 2-3-3 bearded晶格的邊緣態 15 2-3-4 zigzag-bearded晶格的邊緣態 15 2-4 彈簧結構下石墨烯晶格的特徵頻率和頻譜 16 三、彈簧系統下石墨烯晶格模型之推導 20 3-1 有應力情況下彈簧系統總能量 20 3-2 有應力和阻尼情況下彈簧系統的運動方程式 21 3-3 引入旋轉的彈簧系統運動方程式 26 四、模擬結果與討論 28 4-1 無阻尼下彈簧石墨烯模型的邊緣態 28 4-2 加入阻尼下彈簧石墨烯模型的邊緣態 31 4-3 具有PT 對稱之阻尼-增益彈簧石墨烯模型的邊緣態 36 五、結論與未來展望 43 5-1 結論 . 43 5-2 未來展望 43 參考文獻 45

    [1] János K. Asbóth, László Oroszlány, András Pályi, A short course on topological insulators, Springer, 2016
    [2] Klitzing K. v. , Dorda G. and Pepper, M. , “New Method for High-Accuracy Determination of the Fine-Structure Constant Based on Quantized Hall Resistance,” Phys. Rev. Lett. 45, 1980, pp. 494.
    [3] D. J. Thouless, M. Kohmoto, M. P. Nightingale, and M. den Nijs, “Quantized Hall Conductance in a Two-Dimensional Periodic Potential,” Phys. Rev. Lett. 49, 1982, pp. 405
    [4] F. D. M. Haldane, “Model for a Quantum Hall Effect without Landau Levels: Condensed-Matter Realization of the "Parity Anomaly",” Phys. Rev. Lett. 61, 1988, pp. 2015
    [5] Sebastian D. Huber, “Topological mechanics,” NATURE PHYSICS , Vol 12, 2015, pp. 621.
    [6] Levi-Civita, “Notion of Parallelism on a Generic Manifold and Consequent Geometrical Specification of the Riemannian Curvature,” T. Rend. Circ. Mat. Palermo 42, 1917, pp. 173
    [7] Berry, M. V. , “Quantal phase factors accompanying adiabatic changes,” Proc. R. Soc. Lond. A 392, 1984, pp. 45.
    [8] Berry. S. , “Holonomy, the Quantum Adiabatic Theorem, and Berry's Phase,” Phys. Rev. Lett. 51, 1983, pp. 2167.
    [9] Hannay, J. H. , “Angle variable holonomy in adiabatic excursion of an integrable Hamiltonian,” Phys. A 18, 1985, pp. 221.
    [10] Süsstrunk, R. & Huber, S. D. , “Classification of topological phonons in linear mechanical metamaterials,” Proc. Natl. Acad. Sci. USA 113, 2016, E4767.
    [11] 蔡雅雯、吳杰倫、欒丕綱:〈從量子霍爾效應到拓樸光子學與拓樸聲子學〉,《科儀新知》, 211期, 2017, 68頁。
    [12] Mahito Kohmoto,Yasumasa Hasegawa, “Zero modes and edge states of the honeycomb lattice,” Phys. Rev. B 76, 2007, 205402.
    [13] Cserti, J. and G. Tichy, “A simple model for the vibrational modes in honeycomb lattices,” European journal of physics 25, 2004, pp. 723.
    [14] C. Kittel, Introduction to Solid State Physics, global/e. , Wiley, 2018.
    [15] Y.-T. Wang, P.-G. Luan, and S. Zhang, “Coriolis force induced topological order for classical mechanical vibrations,” New Journal of Physics 17, 2015, 073031.
    [16] Liu, Y., et al., “Model for topological phononics and phonon diode,” Phys. Rev. B 96, 2017, 064106.
    [17] J.E. Escalante-M. ,et al. , “Experimental evaluation of viscous dampingcoefficient in the fractional underdamped oscillator,” Advances in Mechnical Engineering, Vol. 8, 2016, pp. 4.
    [18] Kariyado, T. and Y. Hatsugai, “Manipulation of dirac cones in mechanical graphene,” Sci. Rep. 5, 2015, 18107.
    [19] Yu. R. , et al. , “Equivalent expression of Z2 topological invariant for band insulators using the non-Abelian Berry connection,” Phys. Rev. B 84, 2011, 075119.
    [20] Weng, H. , Yu. R. , Xiao Hu, Xi Dai, X. , & Fang, Z, “Quantum anomalous Hall effect and related topological electronic states,” Advances in Physics 64, 2015, pp. 227.
    [21] Erwin Kreyszig, Advanced Engineering Mathematics, 10/e (Taiwan Custom Version), Wiley, 2018.
    [22] Yizhou Liu, Yong Xu, Shou-Cheng Zhang,&Wenhui Duan, “Model for topological phononics and phonon diode,” Phys. Rev. B 96, 2017, 064106.
    [23] Hiromasa Wakao, Tsuneya Yoshida, Hiromu Araki, Tomonari Mizoguchi,& Yasuhiro Hatsugai, “Higher-order topological phases in a spring-mass model on a breathing kagome lattice,” Phys. Rev. B 101, 2020, 094107.

    QR CODE
    :::