Extraordinary transition at the edge of a correlated topological insulator

2025/08/01 by Francesco Parisen Toldin, Toldin, Francesco Parisen, Fakher F. Assaad +3 · 2 citations
Physics and Astronomy · #FOS: Physical sciences #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Physics of Superconductivity and Magnetism #Quantum many-body systems #Statistical Mechanics (cond-mat.stat-mech) #Strongly Correlated Electrons (cond-mat.str-el) #Topological Materials and Phenomena

paper · pdf · doi:10.48550/arxiv.2508.00999

openalex publication_date 2025/08/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

Abstract

The interplay of topology and correlations defines a new playground to study boundary criticality in quantum systems. We employ large scale auxiliary field quantum Monte Carlo simulations to study a two-dimensional Kane-Mele-Hubbard model on the honeycomb lattice with zig-zag edges and the Hubbard U-term tuned to the three-dimensional XY bulk critical point. Upon varying the Hubbard-U term on the edge we observe a boundary phase transition from an ordinary phase with a helical Luttinger liquid edge decoupled from the critical bulk to an extraordinary-log phase characterized by a logarithmically diverging spin stiffness. We find that the spectral functions exhibit distinct features in the two phases giving potential experimental signatures.

Citations

• Boundary criticality in two-dimensional interacting topological insulators
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• Identifying the maximum entropy method as a special limit of stochastic analytic continuation

Cited by

• Boundary criticality in two-dimensional correlated topological superconductors
• Universal Driven Critical Dynamics near the Boundary

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• Fracton Critical Point in Higher-Order Topological Phase Transition
• Boundary deconfined quantum criticality at transitions between symmetry-protected topological chains