Emergent topological phase from a one-dimensional network of defects

TL;DR

This paper demonstrates how a network of periodically modulated defects in a one-dimensional system can give rise to emergent topological phases with tunable properties, observable through transport signatures and robust to disorder.

Contribution

It introduces a defect network model that captures emergent topological phases and shows their stability and experimental realizability on metallic platforms.

Findings

Emergent topological phases arise from defect scattering in a 1D network.

The network model reveals non-trivial winding and boundary phenomena.

Defect engineering enables topological phases without atomic Hamiltonian design.

Abstract

Symmetry-protected topological phases of matter, characterized by non-trivial band topology, are spectrally gapped and show non-trivial boundary phenomena. Here, we show that scattering states when interjected by an array of periodically modulated defects can result in emergent topological phases whose properties can be tuned by modulating the defect strengths. We dub this the Su-Schrieffer-Heeger network. We show that a scattering-matrix network model can capture the emergent symmetries and nontrivial winding of the quasienergy bands, which lead to distinct transport signatures and can be further periodically driven to realize a robust Thouless charge pump. We show that a microscopic lattice model embedded with a defect superlattice yields Bloch minibands that directly map to the network problem. We further verify that the physics we report is stable to disorder and point out concrete experimental solid-state platforms where it is readily realizable. Our work, in contrast to engineering atomic Hamiltonians, shows that defect engineering on metallic platforms can lead to emergent topological phases of quantum matter.