Diffusive metal in a percolating Chern insulator

Fuente: arXiv
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Main Authors: Pachhal, Subrata, Nayak, Naba P., Bera, Soumya, Agarwala, Adhip
Format: Preprint
Published: 2025
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author Pachhal, Subrata
Nayak, Naba P.
Bera, Soumya
Agarwala, Adhip
author_facet Pachhal, Subrata
Nayak, Naba P.
Bera, Soumya
Agarwala, Adhip
contents Two-dimensional non-interacting fermions without any anti-unitary symmetries generically get Anderson localized in the presence of disorder. In contrast, topological superconductors with their inherent particle-hole symmetry can host a thermal metallic phase, which is non-universal and depends on the nature of microscopic disorder. In this work, we demonstrate that in the presence of geometric disorders, such as random bond dilution, a robust metal can emerge in a Chern insulator with particle-hole symmetry. The metallic phase is realized when the broken links are weakly stitched via concomitant insertion of $π$ fluxes in the plaquettes. These nucleate low-energy manifolds, which can provide percolating conduction pathways for fermions to elude localization. This diffusive metal, unlike those in superconductors, can carry charge current and even anomalous Hall current. We investigate the transport properties and show that while the topological insulator to Anderson insulator transition exhibits the expected Dirac universality, the metal insulator transition displays a different critical exponent $ν\approx 2$ compared to a disordered topological superconductor, where $ν\approx 1.4$. Our work emphasizes the unique role of geometric disorder in engineering novel phases and their transitions in topological quantum matter.
format Preprint
id arxiv_https___arxiv_org_abs_2512_24050
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Diffusive metal in a percolating Chern insulator
Pachhal, Subrata
Nayak, Naba P.
Bera, Soumya
Agarwala, Adhip
Mesoscale and Nanoscale Physics
Disordered Systems and Neural Networks
Strongly Correlated Electrons
Two-dimensional non-interacting fermions without any anti-unitary symmetries generically get Anderson localized in the presence of disorder. In contrast, topological superconductors with their inherent particle-hole symmetry can host a thermal metallic phase, which is non-universal and depends on the nature of microscopic disorder. In this work, we demonstrate that in the presence of geometric disorders, such as random bond dilution, a robust metal can emerge in a Chern insulator with particle-hole symmetry. The metallic phase is realized when the broken links are weakly stitched via concomitant insertion of $π$ fluxes in the plaquettes. These nucleate low-energy manifolds, which can provide percolating conduction pathways for fermions to elude localization. This diffusive metal, unlike those in superconductors, can carry charge current and even anomalous Hall current. We investigate the transport properties and show that while the topological insulator to Anderson insulator transition exhibits the expected Dirac universality, the metal insulator transition displays a different critical exponent $ν\approx 2$ compared to a disordered topological superconductor, where $ν\approx 1.4$. Our work emphasizes the unique role of geometric disorder in engineering novel phases and their transitions in topological quantum matter.
title Diffusive metal in a percolating Chern insulator
topic Mesoscale and Nanoscale Physics
Disordered Systems and Neural Networks
Strongly Correlated Electrons
url https://arxiv.org/abs/2512.24050