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arXiv · 2609.20285

Reconfigurable Current Distributions in Percolating Au Films and CrO2 Powder Compacts - Beyond Geometrical Connectivity

E. Yu. Beliayev·I. G. Mirzoiev·V. A. Horielyi
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Abstract

Despite fundamental differences in morphology, dimensionality, and microscopic transport, semicontinuous Au films and compacted CrO2 powders converge on a common network-level principle: the electrically relevant network is a condition-dependent subset of the physical contact network. In Au films near the geometrical percolation threshold, increasing bias reversibly shifts the low-temperature response from activated nearest-neighbour hopping with negative magnetoresistance to a weak-localization-like regime with positive magnetoresistance, consistent with broader electronic participation of the fixed island network. In CrO2 powder compacts, magnetic field mainly changes the spin-dependent resistances of existing intergranular junctions and thereby reorders competing current paths; temperature and measuring current can additionally expand or deplete the active network. Cohn's theorem provides a compact sensitivity principle for both cases: local resistance changes influence the measured response in proportion to the current carried by the affected links. The comparison identifies two limiting but interconvertible modes of reconfiguration - link enabling and link reweighting - and shows why geometrical connectivity alone is insufficient for interpreting transport in strongly inhomogeneous conductors.

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E. Yu. Beliayev, I. G. Mirzoiev, V. A. Horielyi. 2026-07-29. Reconfigurable Current Distributions in Percolating Au Films and CrO2 Powder Compacts - Beyond Geometrical Connectivity. https://arxiv.org/abs/2609.20285

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