Topological phases and Anderson localization in off-diagonal mosaic lattices

TL;DR

This paper introduces a one-dimensional mosaic lattice model with modulated hopping amplitudes, revealing novel topological phases and Anderson localization phenomena, including edge modes and quantized Berry phases, with implications for low-dimensional systems.

Contribution

The study presents a new 1D mosaic lattice model exhibiting unique topological and localization behaviors not seen in regular off-diagonal lattices, including topological edge states and quasiperiodic localization.

Findings

Topologically nontrivial phases with edge modes in commensurate mosaics.

Anderson localization induced by incommensurate quasiperiodic modulations.

Existence of Chern insulators in 2D generalizations of the lattice.

Abstract

We introduce a one-dimensional lattice model whose hopping amplitudes are modulated for equally spaced sites. Such mosaic lattice exhibits many interesting topological and localization phenomena that do not exist in the regular off-diagonal lattices. When the mosaic modulation is commensurate with the underlying lattice, topologically nontrivial phases with zero- and nonzero-energy edge modes are observed as we tune the modulation, where the nontrivial regimes are characterized by quantized Berry phases. If the mosaic lattice becomes incommensurate, Anderson localization will be induced purely by the quasiperiodic off-diagonal modulations. The localized eigenstate is found to be centered on two neighboring sites connected by the quasiperiodic hopping terms. Furthermore, both the commensurate and incommensurate off-diagonal mosaic lattices can host Chern insulators in their two-dimensional generalizations. Our work provides a platform for exploring topological phases and Anderson localization in low-dimensional systems.