Taming quantum interference: a route to high electrical conductance in carbon nanotube assemblies
Abstract
In nanostructured networks, transport is governed by junctions between neighbouring building blocks. Improving their alignment and removing defects is the intuitive route to better electron transport. At low temperatures, when transport becomes coherent, a junction cannot always be reduced to a single effective resistance, because electron-wave interference can strongly enhance or suppress transmission even in nominally ideal junctions. Using carbon nanotube (CNT) networks as a model system, we explore coherent transport through experimentally relevant junctions, from single and multiple single-walled CNT (SWCNT) contacts to double-walled CNT (DWCNT) and multi-walled CNT (MWCNT) junctions, with atomistic tight-binding non-equilibrium Green's-function calculations, also under a perpendicular magnetic field. We use analytically solvable minimal models to identify transport regimes expected for quasi-1D nanoscale junctions, and an electron-waveguide picture to interpret their CNT-specific manifestations. For single SWCNT--SWCNT junctions, high-transmission windows are set mainly by overlap length, doping and magnetic field. Gateway states can enhance conductance when some CNT subbands are gapped, and in some cases a magnetic field can restore transmission by lifting an interference blockade. In more complex architectures, added paths become selective: multi-junctions generate resonant filtering, while additional walls redistribute transmission instead of acting as independent channels. DWCNT junctions remain outer-wall dominated and SWCNT-like, whereas MWCNT junctions redistribute transmission among coupled walls and show a more complex field response. Our ultrahigh-field measurements likewise show lower, more field-sensitive conductance in MWCNT than SWCNT fibres. This work turns microscopic interference mechanisms into design principles for high-conductance, field-stable CNT conductors.
Versions
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BibTeX
@misc{kulka2026taming,
title = {{Taming quantum interference: a route to high electrical conductance in carbon nanotube assemblies}},
author = {Teresa Kulka and Agnieszka E. Lekawa-Raus and John S. Bulmer and Krzysztof Koziol and Fedor F. Balakirev and Irina V. Lebedeva and Jacek A. Majewski and Magdalena Marganska and Karolina Z. Milowska},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2605.28250},
eprint = {2605.28250},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2605.28250},
}
RIS
TY - UNPB
TI - Taming quantum interference: a route to high electrical conductance in carbon nanotube assemblies
AU - Teresa Kulka
AU - Agnieszka E. Lekawa-Raus
AU - John S. Bulmer
AU - Krzysztof Koziol
AU - Fedor F. Balakirev
AU - Irina V. Lebedeva
AU - Jacek A. Majewski
AU - Magdalena Marganska
AU - Karolina Z. Milowska
PY - 2026
DA - 2026/09/10
PB - arXiv
DO - 10.48550/arxiv.2605.28250
UR - https://arxiv.org/abs/2605.28250
AB - In nanostructured networks, transport is governed by junctions between neighbouring building blocks. Improving their alignment and removing defects is the intuitive route to better electron transport. At low temperatures, when transport becomes coherent, a junction cannot always be reduced to a single effective resistance, because electron-wave interference can strongly enhance or suppress transmission even in nominally ideal junctions. Using carbon nanotube (CNT) networks as a model system, we explore coherent transport through experimentally relevant junctions, from single and multiple single-walled CNT (SWCNT) contacts to double-walled CNT (DWCNT) and multi-walled CNT (MWCNT) junctions, with atomistic tight-binding non-equilibrium Green's-function calculations, also under a perpendicular magnetic field. We use analytically solvable minimal models to identify transport regimes expected for quasi-1D nanoscale junctions, and an electron-waveguide picture to interpret their CNT-specific manifestations. For single SWCNT--SWCNT junctions, high-transmission windows are set mainly by overlap length, doping and magnetic field. Gateway states can enhance conductance when some CNT subbands are gapped, and in some cases a magnetic field can restore transmission by lifting an interference blockade. In more complex architectures, added paths become selective: multi-junctions generate resonant filtering, while additional walls redistribute transmission instead of acting as independent channels. DWCNT junctions remain outer-wall dominated and SWCNT-like, whereas MWCNT junctions redistribute transmission among coupled walls and show a more complex field response. Our ultrahigh-field measurements likewise show lower, more field-sensitive conductance in MWCNT than SWCNT fibres. This work turns microscopic interference mechanisms into design principles for high-conductance, field-stable CNT conductors.
ER -