Topological insulators (TIs) are a new class of materials that resemble ordinary band insulators in terms of a bulk band gap but exhibit protected metallic states on their boundaries. In this modern direction, higher-order TIs (HOTIs) are a new class of TIs in dimensions d > 1. These HOTIs possess (d − 1)-dimensional boundaries that, unlike those of conventional TIs, do not conduct via gapless states but are themselves TIs. Recent years have witnessed tremendous development in these fields where out-of-equilibrium topological characters are induced by periodic Floquet drive starting from the trivial limit [1]. I will discuss our contributions to the field of Floquet topological higher-order phases [2,3]. In parallel, the Hermitian physics of TI is drastically modified in the non-Hermitian (NH) cases where the parallel nature of the eigenvectors and associated exceptional degeneracies yield various intriguing phenomena such as the breakdown of conventional bulk boundary correspondence and the emergence of skin modes [4]. I will highlight our contribution to this field of NH Floquet topological phases where multiple interesting phenomena take place in terms of their topological characterization and boundary localization [5,6].

[1] Topical review: J. Phys.: Condens. Matter 36, 093001 (2024), Arnob Kumar Ghosh, Tanay Nag, Arijit Saha.

[2] Phys. Rev. B 103, 115308 (2021), Tanay Nag, Vladimir Juricic, Bitan Roy.

[3] Phys. Rev. B 105, 115418 (2022), Arnob Kumar Ghosh, Tanay Nag, Arijit Saha.

[4] Rev. Mod. Phys. 93, 015005 (2021), E. J. Bergholtz, J. C. Budich, and F. K. Kunst.

[5] Phys. Rev. B 106, L140303 (2022), Arnob Kumar Ghosh, Tanay Nag.

[6] "Corner modes in Non-Hermitian long-range model", Arnob Kumar Ghosh, Arijit Saha, Tanay Nag (submitted).

Meeting ID: 964 7295 8730
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