Floquet second-order topological Anderson insulator hosting corner localized modes

Abstract

The presence of random disorder in a metallic system accounts for the localization of extended states in general. On the contrary, the presence of disorder can induce topological phases hosting metallic boundary states out of a non-topological system, giving birth to the topological Anderson insulator phase. In this context, we theoretically investigate the generation of an out of equilibrium higher-order topological Anderson phase in the presence of disorder potential in a time-periodic dynamical background. In particular, the time-dependent drive and the disorder potential concomitantly render the generation of Floquet higher-order topological Anderson insulator~(FHOTAI) phase, while the clean, undriven system is topologically trivial. We showcase the generation of FHOTAI hosting both $0$- and $\pi$-modes. Most importantly, we develop the real space topological invariant -- a winding number based on chiral symmetry to characterize the Floquet $0$- and $\pi$-modes distinctly. This chiral winding number serves the purpose of the indicator for the topological phase transition in the presence of drive as well as disorder and appropriately characterizes the FHOTAI.