Steering of topological criticality in the Su-Schrieffer-Heeger chain via non-Hermitian substitutional impurities
Abstract
We investigate the topological phase in a one-dimensional Su-Schrieffer-Heeger (SSH) chain in the presence of a finite concentration of non-Hermitian substitutional impurities. Our primary focus is the discovery of a deterministic mechanism to actively reconfigure the topological phase boundaries by introducing site-dependent, non-reciprocal intracell and intercell hopping amplitudes. Specifically, breaking the internal structural symmetry of the non-reciprocal impurity hoppings induces a targeted macroscopic displacement of the critical point. This mechanism allows for the controlled expansion or compression of the topological phase strictly via local defect asymmetry. We validate this boundary displacement through finite-size scaling analysis. The extracted correlation length critical exponents (ν≈ 1.455 and ν≈ 1.397 for symmetric and asymmetric configurations, respectively) confirm a disorder-induced departure from the pristine SSH universality class, with the exponent diverging at high defect densities. We also report an impurity-induced real-to-complex spectral transition geometrically characterized by the Non-Hermitian Skin Effect. Ultimately, our results establish how isolated non-Hermitian asymmetries cooperatively interact to deterministically shift macroscopic topological protection.
Related
- Initial-state-dependent dephasing effect in non-Hermitian Su-Schrieffer-Heeger models
- Transport properties and topological phase transitions for a Creutz-Su-Schrieffer-Heeger ladder
- Substrate-driven topological engineering in plasmonic Su-Schrieffer-Heeger chains
- Statistics-controlled topological phases in a Su-Schrieffer-Heeger ladder
- Emergent de Sitter Space and Non-Unitary Tensor Networks from Non-Hermitian Quantum Criticality
BibTeX
@misc{canas2026steering,
title = {{Steering of topological criticality in the Su-Schrieffer-Heeger chain via non-Hermitian substitutional impurities}},
author = {Juan A. Cañas and Guo-Qing Zhang and A. Martín-Ruiz},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.27436},
eprint = {2610.27436},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.27436},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Steering of topological criticality in the Su-Schrieffer-Heeger chain via non-Hermitian substitutional impurities
AU - Juan A. Cañas
AU - Guo-Qing Zhang
AU - A. Martín-Ruiz
PY - 2026
DA - 2026/10/20
PB - arXiv
DO - 10.48550/arxiv.2610.27436
UR - https://arxiv.org/abs/2610.27436
AB - We investigate the topological phase in a one-dimensional Su-Schrieffer-Heeger (SSH) chain in the presence of a finite concentration of non-Hermitian substitutional impurities. Our primary focus is the discovery of a deterministic mechanism to actively reconfigure the topological phase boundaries by introducing site-dependent, non-reciprocal intracell and intercell hopping amplitudes. Specifically, breaking the internal structural symmetry of the non-reciprocal impurity hoppings induces a targeted macroscopic displacement of the critical point. This mechanism allows for the controlled expansion or compression of the topological phase strictly via local defect asymmetry. We validate this boundary displacement through finite-size scaling analysis. The extracted correlation length critical exponents (ν≈ 1.455 and ν≈ 1.397 for symmetric and asymmetric configurations, respectively) confirm a disorder-induced departure from the pristine SSH universality class, with the exponent diverging at high defect densities. We also report an impurity-induced real-to-complex spectral transition geometrically characterized by the Non-Hermitian Skin Effect. Ultimately, our results establish how isolated non-Hermitian asymmetries cooperatively interact to deterministically shift macroscopic topological protection.
ER -