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Breakdown of the Wiedemann-Franz Law in an Interacting Quantum Hall Metamaterial
Phys. Rev. Lett. 136, 196301 – Published 12 May, 2026
DOI: https://doi.org/10.1103/twbt-z82z
Abstract
Coulomb interactions deeply affect quantum transport in simple ballistic systems, but their impact on scaled up ballistic structures remains underexplored. Here, we theoretically consider a chain of small metallic dots with frozen charge dynamics connected by ballistic channels. We identify a neutral mode of transport that is specific to a chain with at least two islands and entwines local diffusion by neutral excitations with long-range correlations between the islands’ charge states. We show, as an experimentally measurable signature of this many-body behavior, that the Wiedemann-Franz law is violated with a Lorenz ratio scaling as the square root of the chain’s length.