Atomic-Scale Terahertz Near Fields for Ultrafast Tunnelling Spectroscopy

Fuente: arXiv
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Autori principali: Jelic, Vedran, Adams, Stefanie, Hassan, Mohamed, Cleland-Host, Kaedon, Ammerman, S. Eve, Cocker, Tyler L.
Natura: Preprint
Pubblicazione: 2023
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author Jelic, Vedran
Adams, Stefanie
Hassan, Mohamed
Cleland-Host, Kaedon
Ammerman, S. Eve
Cocker, Tyler L.
author_facet Jelic, Vedran
Adams, Stefanie
Hassan, Mohamed
Cleland-Host, Kaedon
Ammerman, S. Eve
Cocker, Tyler L.
contents Lightwave-driven terahertz scanning tunnelling microscopy (THz-STM) is capable of exploring ultrafast dynamics across a wide range of materials with angstrom resolution. In contrast to scanning near-field optical microscopy, where photons scattered by the tip apex are analyzed to access the local dielectric function on the nanoscale, THz-STM uses a strong-field single-cycle terahertz pulse to drive an ultrafast current across a tunnel junction, thereby probing the local density of electronic states. Yet, the terahertz field in a THz-STM junction may also be spectrally modified by the electromagnetic response of the sample. Here, we demonstrate a reliable and self-consistent approach for terahertz near-field waveform acquisition in an atomic tunnel junction that can be generally applied to electrically conductive surfaces. By combining waveform sampling and tailoring with terahertz scanning tunnelling spectroscopy (THz-STS), we comprehensively characterize the tunnel junction and distinguish local sample properties from effects due to terahertz pulse coupling and field enhancement. Through modelling, we verify the presence of an isolated unipolar terahertz-induced current pulse, facilitating straightforward interpretation for differential THz-STS with high spectral resolution. Finally, we demonstrate the feasibility of atomic-scale terahertz time-domain spectroscopy via the extremely localized near-fields in the tunnel junction.
format Preprint
id arxiv_https___arxiv_org_abs_2310_14335
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Atomic-Scale Terahertz Near Fields for Ultrafast Tunnelling Spectroscopy
Jelic, Vedran
Adams, Stefanie
Hassan, Mohamed
Cleland-Host, Kaedon
Ammerman, S. Eve
Cocker, Tyler L.
Mesoscale and Nanoscale Physics
Lightwave-driven terahertz scanning tunnelling microscopy (THz-STM) is capable of exploring ultrafast dynamics across a wide range of materials with angstrom resolution. In contrast to scanning near-field optical microscopy, where photons scattered by the tip apex are analyzed to access the local dielectric function on the nanoscale, THz-STM uses a strong-field single-cycle terahertz pulse to drive an ultrafast current across a tunnel junction, thereby probing the local density of electronic states. Yet, the terahertz field in a THz-STM junction may also be spectrally modified by the electromagnetic response of the sample. Here, we demonstrate a reliable and self-consistent approach for terahertz near-field waveform acquisition in an atomic tunnel junction that can be generally applied to electrically conductive surfaces. By combining waveform sampling and tailoring with terahertz scanning tunnelling spectroscopy (THz-STS), we comprehensively characterize the tunnel junction and distinguish local sample properties from effects due to terahertz pulse coupling and field enhancement. Through modelling, we verify the presence of an isolated unipolar terahertz-induced current pulse, facilitating straightforward interpretation for differential THz-STS with high spectral resolution. Finally, we demonstrate the feasibility of atomic-scale terahertz time-domain spectroscopy via the extremely localized near-fields in the tunnel junction.
title Atomic-Scale Terahertz Near Fields for Ultrafast Tunnelling Spectroscopy
topic Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2310.14335