Topological insulator phases in 2D materials
An important goal in condensed matter physics is the classification of phases of matter. In the past, unprecedented efforts have been devoted to the exploration of novel topological phases and of their remarkable properties at their boundaries [1]. In two dimensions (2D), their hallmark is the presence of propagating edge states which carry dissipationless current. These unusual transport properties depend crucially on the nature of the bulk energy gaps and the associated topological invariants together with the underlying symmetries of the system. For instance, the quantum spin hall (QSH) insulator has gapless edge states which are possible due to the combination of spin-orbit coupling and the preservation of time-reversal symmetry. I will first discuss the Berry phase of 2D Dirac fermions, topological band theory, topological invariants, and symmetries. The emergence of the QSH phase, the quantum anomalous Hall phase, and the Floquet topological insulator will then be discussed [2].
[1] B. A. Bernevig and T. L. Hughes, Topological Insulators and Topological Superconductors (Princeton University Press, Princeton, 2013).
[2] V. Vargiamidis et al., Phys. Rev. B 106, 205416 (2022); Phys. Rev. B 112, 045406 (2025).
This IFISC Seminar will be broadcasted in the following zoom link: https://us06web.zoom.us/j/89027654460?pwd=Wg9TYMPqqP2ipfj2JVvEagmzaTw29c.1
Coffee and cookies will be served 15 minutes before the start of the seminar
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