Conductance channels of a platform molecule on Au(111) probed with shot noise

Mohr, Michael; Jasper-Toennies, Torben; Frederiksen, Thomas; García-Lekue, Aran; Ulrich, Sandra; Herges, Rainer; Berndt, Richard

doi:10.1103/physrevb.99.245417

Cited by 14 publications

(15 citation statements)

References 33 publications

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“…What did we achieve? Obviously, if τ (ǫ) were entirely known experimentally, the electronic current noise could be obtained directly from a numerical integration of the formal equation (13). However, as a next kin to the transmission function we only have an access to the differential conductance, whose structure at low temperature allows us to deduce on the variation of the transmission function with energy.…”

Section: Discussionmentioning

confidence: 99%

Origin of the Anomalous Electronic Shot Noise in Atomic-Scale Junctions

Shein-Lumbroso

Tal

et al. 2019

J. Phys. Chem. C

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Fluctuations pose fundamental limitations in making sensitive measurements, yet at the same time, noise unravels properties that are inaccessible at the level of the averaged signal. In electronic devices, shot noise arises from the discrete nature of charge carriers and it increases linearly with the applied voltage according to the celebrated Schottky formula. Nonetheless, measurements of shot noise in atomic-scale junctions at high voltage reveal significant nonlinear (anomalous) behavior, which varies from sample to sample, and has no specific trend. Here, we provide a viable, unifying explanation for these diverse observations based on the theory of quantum coherent transport.Our formula for the anomalous shot noise relies on-and allows us to resolve-two key characteristics of a conducting junction: The structure of the transmission function at the vicinity of the Fermi energy and the asymmetry of the bias voltage drop at the contacts. We tested our theory on high voltage shot noise measurements on Au atomic scale junctions and demonstrated a quantitative agreement, recovering both the enhancement and suppression of shot noise as observed in different junctions. The good theory-experiment correspondence supports our modelling and emphasizes that the asymmetry of the bias drop on the contacts is a key factor in nanoscale electronic transport, which may substantially impact electronic signals even in incomplex structures.

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Section: Discussionmentioning

confidence: 99%

Origin of the Anomalous Electronic Shot Noise in Atomic-Scale Junctions

Shein-Lumbroso

Tal

et al. 2019

J. Phys. Chem. C

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“…Noise in mesoscopic structures has been investigated in some detail 3 , noise spectroscopy of atomic [4][5][6][7][8][9][10][11][12][13][14][15] and molecular [16][17][18][19][20][21][22] junctions, however, is a more recent development. No data have been reported from molecules that are likely to exhibit spin-dependent transport.…”

Section: Introductionmentioning

confidence: 99%

Spin dependent transmission of nickelocene-Cu contacts probed with shot noise

et al. 2020

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The current I through nickelocene molecules and its noise are measured with a low temperature scanning tunneling microscope on a Cu(100) substrate. Density functional theory calculations and many-body modeling are used to analyze the data. During contact formation, two types of current evolution are observed, an abrupt jump to contact and a smooth transition. These data along with conductance spectra (dI/dV ) recorded deep in the contact range are interpreted in terms of a transition from a spin-1 to a spin-1 /2 state that is Kondo screened. Many-body calculations show that the smooth transition is also consistent with a renormalization of spin excitations of a spin-1 molecule by Kondo exchange coupling. The shot noise is significantly reduced compared to the Schottky value of 2eI but no influence of the Kondo effect or spin excitations are resolved. The noise can be described in the Landauer picture in terms of spin-polarized transmission of ≈ 35 % through two degenerate dπ-orbitals of the Nickelocene molecule.

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“…Investigations of shot noise with STM are still fairly few in number [25][26][27][28][29][30][31][32]. Here we present results from single Fe atoms on Au(111) surfaces that are hydrogenated in a low-temperature scanning tunneling microscope (STM).…”

Section: Introductionmentioning

confidence: 94%

Current shot noise in atomic contacts: Fe and FeH$_2$ between Au electrodes

Mohr,

Weismann,

et al. 2021

Preprint

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Single Fe atoms on Au(111) surfaces were hydrogenated and dehydrogenated with the Au tip of a low-temperature scanning tunneling microscope (STM). Fe and FeH2 were contacted with the tip of the microscope and show distinctly different evolutions of the conductance with the tip-substrate distance. The current shot noise of these contacts has been measured and indicates a single relevant conductance channel with the spin-polarized transmission. For FeH2 the spin polarization reaches values up to 80% for low conductances and is reduced if the tip-surface distance is decreased. These observations are partially reproduced using density functional theory (DFT) based transport calculations. We suggest that the quantum motion of the hydrogen atoms, which is not taken into account in our DFT modeling, may have a significant effect on the results.

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Conductance channels of a platform molecule on Au(111) probed with shot noise

Cited by 14 publications

References 33 publications

Origin of the Anomalous Electronic Shot Noise in Atomic-Scale Junctions

Origin of the Anomalous Electronic Shot Noise in Atomic-Scale Junctions

Spin dependent transmission of nickelocene-Cu contacts probed with shot noise

Current shot noise in atomic contacts: Fe and FeH$_2$ between Au electrodes

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