Floquet second-order topological insulators in non-Hermitian systems
Abstract
Second-order topological insulator (SOTI) is featured with the presence of -dimensional boundary states in -dimension systems. The non-Hermiticity induced breakdown of bulk-boundary correspondence (BBC) and the periodic driving on systems generally obscure the description of non-Hermitian SOTI. To prompt the applications of SOTIs, we explore the role of periodic driving in controllably creating exotic non-Hermitian SOTIs both for 2D and 3D systems. A scheme to retrieve the BBC and a complete description to SOTIs via the bulk topology of such nonequilibrium systems are proposed. It is found that rich exotic non-Hermitian SOTIs with a widely tunable number of 2D corner states and 3D hinge states and a coexistence of the first- and second-order topological insulators are induced by the periodic driving. Enriching the family of topological phases, our result may inspire the exploration to apply SOTIs via tuning the number of corner/hinge states by the periodic driving.
Cite
@article{arxiv.2008.06879,
title = {Floquet second-order topological insulators in non-Hermitian systems},
author = {Hong Wu and Bao-Qin Wang and Jun-Hong An},
journal= {arXiv preprint arXiv:2008.06879},
year = {2021}
}