Negative differential conductance in triangular molecular assemblies

Fuente: arXiv
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Auteurs principaux: Li, Chao, Pokorný, Vladislav, Hapala, Prokop, Žonda, Martin, Zhou, Ping, Decurtins, Silvio, Liu, Shi-Xia, Song, Fengqi, Pawlak, Rémy, Meyer, Ernst
Format: Preprint
Publié: 2025
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author Li, Chao
Pokorný, Vladislav
Hapala, Prokop
Žonda, Martin
Zhou, Ping
Decurtins, Silvio
Liu, Shi-Xia
Song, Fengqi
Pawlak, Rémy
Meyer, Ernst
author_facet Li, Chao
Pokorný, Vladislav
Hapala, Prokop
Žonda, Martin
Zhou, Ping
Decurtins, Silvio
Liu, Shi-Xia
Song, Fengqi
Pawlak, Rémy
Meyer, Ernst
contents We report the creation and characterization of a molecular-scale negative differential conductance (NDC) device by assembling a triangular trimer of 4,5,9,10-tetrabromo-1,3,6,8-tetraazapyrene (TBTAP) molecules on a superconducting Pb(111) substrate. Using low-temperature scanning tunneling spectroscopy, we observe robust NDC behavior manifesting as a decrease in current with increasing voltage between 0.7-0.9 V arising from the interplay of Coulomb blockade and strong inter-molecular capacitive coupling within the molecular cluster. Gate-controlled charging and discharging processes are directly visualized via two-dimensional differential conductance mapping, which reveals the emergence of Coulomb rings and spatial regions of NDC. Theoretical modeling using a three-impurity Anderson model and master equation approach quantitatively reproduces the experimental observations and demonstrates that the NDC emerges purely from electron correlations, independent of the underlying superconductivity. By tuning the geometry to a hexamer structure, we further show that cluster topology provides versatile control over electronic properties at the molecular scale. These results establish a functional platform for implementing multifunctional molecular devices and highlight a strategy toward programmable and scalable nanoelectronics.
format Preprint
id arxiv_https___arxiv_org_abs_2508_05575
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Negative differential conductance in triangular molecular assemblies
Li, Chao
Pokorný, Vladislav
Hapala, Prokop
Žonda, Martin
Zhou, Ping
Decurtins, Silvio
Liu, Shi-Xia
Song, Fengqi
Pawlak, Rémy
Meyer, Ernst
Mesoscale and Nanoscale Physics
We report the creation and characterization of a molecular-scale negative differential conductance (NDC) device by assembling a triangular trimer of 4,5,9,10-tetrabromo-1,3,6,8-tetraazapyrene (TBTAP) molecules on a superconducting Pb(111) substrate. Using low-temperature scanning tunneling spectroscopy, we observe robust NDC behavior manifesting as a decrease in current with increasing voltage between 0.7-0.9 V arising from the interplay of Coulomb blockade and strong inter-molecular capacitive coupling within the molecular cluster. Gate-controlled charging and discharging processes are directly visualized via two-dimensional differential conductance mapping, which reveals the emergence of Coulomb rings and spatial regions of NDC. Theoretical modeling using a three-impurity Anderson model and master equation approach quantitatively reproduces the experimental observations and demonstrates that the NDC emerges purely from electron correlations, independent of the underlying superconductivity. By tuning the geometry to a hexamer structure, we further show that cluster topology provides versatile control over electronic properties at the molecular scale. These results establish a functional platform for implementing multifunctional molecular devices and highlight a strategy toward programmable and scalable nanoelectronics.
title Negative differential conductance in triangular molecular assemblies
topic Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2508.05575