Reconfigurable Current Distributions in Percolating Au Films and CrO2 Powder Compacts - Beyond Geometrical Connectivity
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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BibTeX
@misc{beliayev2026reconfigurable,
title = {{Reconfigurable Current Distributions in Percolating Au Films and CrO2 Powder Compacts - Beyond Geometrical Connectivity}},
author = {E. Yu. Beliayev and I. G. Mirzoiev and V. A. Horielyi},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.20285},
eprint = {2609.20285},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.20285},
}
RIS
TY - UNPB
TI - Reconfigurable Current Distributions in Percolating Au Films and CrO2 Powder Compacts - Beyond Geometrical Connectivity
AU - E. Yu. Beliayev
AU - I. G. Mirzoiev
AU - V. A. Horielyi
PY - 2026
DA - 2026/09/01
PB - arXiv
DO - 10.48550/arxiv.2609.20285
UR - https://arxiv.org/abs/2609.20285
AB - 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.
ER -