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| Main Authors: | , , , , , , |
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| Format: | Preprint |
| Published: |
2023
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2310.07479 |
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| _version_ | 1866918337138655232 |
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| author | Lassen, Henrik B. Carstensen, William V. Iliushyn, Leonid Booth, Timothy J. Bøggild, Peter Kelleher, Edmund J. R. Jepsen, Peter U. |
| author_facet | Lassen, Henrik B. Carstensen, William V. Iliushyn, Leonid Booth, Timothy J. Bøggild, Peter Kelleher, Edmund J. R. Jepsen, Peter U. |
| contents | As photonic and electronic technologies approach nanometre length scales and terahertz operating speeds, electrical conductivity can no longer be treated as a purely local material parameter. In this regime, charge transport becomes intrinsically nonlocal, with conductivity depending on both frequency and momentum, $σ(ω,q)$, fundamentally limiting field confinement, dispersion, and loss in nanoscale devices. Here, we directly measure the nonlocal nanoscale conductivity of graphene using terahertz scattering-type near-field optical microscopy. By combining broadband THz near-field spectroscopy with quantitative electrodynamic modelling, we extract the complex conductivity of single- and few-layer graphene with $\sim$50 nm spatial resolution. We find that nonlocal response dominates the terahertz conductivity of monolayer graphene even at length scales comparable to practical device dimensions. These results establish nonlocal conductivity as a measurable and design-relevant material property in the terahertz regime, providing a quantitative foundation for predicting performance limits in ultracompact photonic and electronic systems. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2310_07479 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | Terahertz s-SNOM reveals nonlocal nanoscale conductivity of graphene Lassen, Henrik B. Carstensen, William V. Iliushyn, Leonid Booth, Timothy J. Bøggild, Peter Kelleher, Edmund J. R. Jepsen, Peter U. Optics Materials Science As photonic and electronic technologies approach nanometre length scales and terahertz operating speeds, electrical conductivity can no longer be treated as a purely local material parameter. In this regime, charge transport becomes intrinsically nonlocal, with conductivity depending on both frequency and momentum, $σ(ω,q)$, fundamentally limiting field confinement, dispersion, and loss in nanoscale devices. Here, we directly measure the nonlocal nanoscale conductivity of graphene using terahertz scattering-type near-field optical microscopy. By combining broadband THz near-field spectroscopy with quantitative electrodynamic modelling, we extract the complex conductivity of single- and few-layer graphene with $\sim$50 nm spatial resolution. We find that nonlocal response dominates the terahertz conductivity of monolayer graphene even at length scales comparable to practical device dimensions. These results establish nonlocal conductivity as a measurable and design-relevant material property in the terahertz regime, providing a quantitative foundation for predicting performance limits in ultracompact photonic and electronic systems. |
| title | Terahertz s-SNOM reveals nonlocal nanoscale conductivity of graphene |
| topic | Optics Materials Science |
| url | https://arxiv.org/abs/2310.07479 |