Compton profile of few-layer graphene investigated by electron energy-loss spectroscopy

Feng, Zhenbao; Zhang, Xiaoyan; Sakurai, Y.; Wang, Zongliang; Li, Hefu; Hu, Haiquan

doi:10.1038/s41598-019-53928-2

Cited by 11 publications

(5 citation statements)

References 32 publications

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“…We find this observation a solid argument in favour of DFT as a theoretical framework for computing the graphene response function W . This conclusion is also corroborated by the good agreement found between the measured and DFT-calculated graphene Compton profile [57], which is the longitudinal projection of the electron momentum density, and thus closely related to W .…”

Section: Motivationssupporting

confidence: 69%

Direct searches for general dark matter-electron interactions with graphene detectors: Part I. Electronic structure calculations

Emken¹,

Maťaš²,

Spaldin³

et al. 2023

Preprint

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We develop a formalism to describe electron ejections from graphene-like targets by dark matter (DM) scattering for general forms of scalar and spin 1/2 DM-electron interactions and compare their applicability and accuracy within the density functional theory (DFT) and tight binding (TB) approaches. This formalism allows for accurate prediction of the daily modulation signal expected from DM in upcoming direct detection experiments employing graphene sheets as the target material. A key result is that the physics of the graphene sheet and that of the DM and the ejected electron factorise, allowing for the rate of ejections from all forms of DM to be obtained with a single graphene response function. We perform a comparison between the TB and DFT approaches to modeling the initial state electronic wavefunction within this framework, with DFT emerging as the more self-consistent and reliable choice due to the challenges in the embedding of an appropriate atomic contribution into the TB approach.

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Section: Motivationssupporting

confidence: 69%

Direct searches for general dark matter-electron interactions with graphene detectors: Part I. Electronic structure calculations

Emken¹,

Maťaš²,

Spaldin³

et al. 2023

Preprint

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show abstract

“…Our framework combines effective theory methods -used to describe the interaction between DM and electrons in a general manner [31] -with density functional theory (DFT) in order to express the rate of DM-induced electron ejections from graphene-based targets in terms of a single graphene response function. Remarkably, the latter is directly related to the "diagonal part" of the electron momentum density, which by construction is a solid output of DFT [32,33]. We then applied this framework to calculate the expected daily modulation of the rate of DM-induced electron ejections from a hypothetical detector using graphene as a target material.…”

Section: Introductionmentioning

confidence: 99%

Direct searches for general dark matter-electron interactions with graphene detectors: Part II. Sensitivity studies

Emken¹,

Maťaš²,

Spaldin³

et al. 2023

Preprint

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We use a formalism that describes electron ejections from graphene-like targets by dark matter (DM) scattering for general forms of scalar and spin 1/2 DM-electron interactions in combination with state-of-the-art density functional calculations to produce predictions and reach estimates for various possible carbon-based detector designs. Our results indicate the importance of a proper description of the target electronic structure. In addition, we find a strong dependence of the predicted observed signal for different DM candidate masses and interaction types on the detailed geometry and design of the detector. Combined with directional background vetoing, these dependencies will enable the identification of DM particle properties once a signal has been established.

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“…However, they can also be beneficial when dopants are added to control the type of doping and the carrier concentration [ 20 , 21 , 22 , 23 ]. The scattering of electrons in single and few-layer graphene, caused by the impact of the substrate, surface contamination, and the effects of static distortions and phonons is still the subject of extensive discussions [ 24 , 25 , 26 , 27 , 28 ]. In particular, a strong sublinear dependence of the conductivity over a wide range of carrier concentrations at room temperature was observed by the authors of the study [ 29 ].…”

Section: Introductionmentioning

confidence: 99%

Electrical and Structural Characterization of Few-Layer Graphene Sheets on Quartz

et al. 2022

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Despite the impressive performance and incredible promise for a variety of applications, the wide-scale commercialization of graphene is still behind its full potential. One of the main challenges is related to preserving graphene’s unique properties upon transfer onto practically desirable substrates. In this work, few-layer graphene sheets deposited via liquid-phase transfer from copper onto a quartz substrate have been studied using a suite of experimental techniques, including scanning electron microscopy (SEM), Raman spectroscopy, admittance spectroscopy, and four-point probe electrical measurements. SEM measurements suggest that the transfer of graphene from copper foil to quartz using the aqueous solution of ammonium persulfate was accompanied by unintentional etching of the entire surface of the quartz substrate and, as a result, the formation of microscopic facet structures covering the etched surface of the substrate. As revealed by Raman spectroscopy and the electrical measurements, the transfer process involving the etching of the copper foil in a 0.1 M solution of (NH4)2S2O8 resulted in its p-type doping. This was accompanied by the appearance of an electronic gap of 0.022 eV, as evidenced by the Arrhenius analysis. The observed increase in the conductance of the samples with temperature can be explained by thermally activated carrier transport, dominating the scattering processes.

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Compton profile of few-layer graphene investigated by electron energy-loss spectroscopy

Cited by 11 publications

References 32 publications

Direct searches for general dark matter-electron interactions with graphene detectors: Part I. Electronic structure calculations

Direct searches for general dark matter-electron interactions with graphene detectors: Part I. Electronic structure calculations

Direct searches for general dark matter-electron interactions with graphene detectors: Part II. Sensitivity studies

Electrical and Structural Characterization of Few-Layer Graphene Sheets on Quartz

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