American Chemical Society
jz4c00387_si_001.pdf (1.16 MB)

Breakdown of Ohm’s Law in Molecular Junctions with Electrodes of Single-Layer Graphene

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journal contribution
posted on 2024-03-15, 16:15 authored by Ioan Bâldea, Yuhong Chen, Miao Zhang, Na Xin, Yunxia Feng, Jiajun Feng, Chuancheng Jia, Xuefeng Guo, Zuoti Xie
For sufficiently low biases, Ohm’s law, the cornerstone of electricity, stating that current I and voltage V are proportional, is satisfied at low biases for all known systems ranging from macroscopic conductors to nanojunctions. In this study, we predict theoretically and demonstrate experimentally that in single-molecule junctions fabricated with single-layer graphene as electrodes the current at low V scales as the cube of V, thereby invalidating Ohm’s law. The absence of the ohmic regime is a direct consequence of the unique band structure of the single-layer graphene, whose vanishing density of states at the Dirac points precludes electron transfer from and to the electrodes at low biases.