Computing C1&lt;I&gt;s&lt;/I&gt; X-ray Absorption for Single-Walled Carbon Nanotubes with Distinct Electronic Type

Mowbray, D. J.; Ayala, Paola; Pichler, Thomas; Rubio, Ángel

doi:10.1166/mex.2011.1027

Cited by 11 publications

(16 citation statements)

References 22 publications

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“…(13). As we have previously shown, 33 the dependence of the excitation intensity and frequency on the propagation direction Q/Q is negligible. Therefore, it is appropriate to calculate the average value of …”

Section: Energy Loss Of a Blinking Point Charge Close To The Grasupporting

confidence: 51%

“…Also we can see the splitting of the π plasmon for higher wave vectors, starting from Q ≈ 0.2 a.u., which is a consequence of π -plasmon dispersion anisotropy. Namely, as shown before, 33 the π plasmon splits only if it propagates in the -M direction, so here the splitting is a consequence of calculating the average value over high-symmetry directions. At higher frequencies, at about 14 eV at the point, we can see a very broad π + σ plasmon.…”

Section: Energy Loss Of a Blinking Point Charge Close To The Gramentioning

confidence: 84%

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Ab initiostudy of energy loss and wake potential in the vicinity of a graphene monolayer

et al. 2012

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A propagator of the dynamically screened Coulomb interaction in the vicinity of a graphene monolayer is calculated using ground-state Kohn-Sham orbitals, and the imaginary part of this propagator is used to calculate the energy-loss rate of a static blinking point charge due to excitation of electronic modes in graphene. Energy loss calculated for all (Q,ω) modes gives intensities of electronic excitations, including plasmon dispersions in graphene, with low-energy two-dimensional (2D) and high-energy π 1 , π 2 , and π + σ plasmons. Plasmon energies are in good agreement with experimental results. This spectral analysis also enables us to study the contribution of each plasmon mode to the stopping power and potential induced by a point charge moving parallel to the graphene. We find the bow waves that in pristine graphene appear for higher velocities (v 2v F ) and predominantly originate from excitation of π plasmons. Doping induces extra features which appear for lower v ≈ v F velocities and predominantly originate from the excitation of 2D or Drude plasmons.

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Section: Energy Loss Of a Blinking Point Charge Close To The Grasupporting

confidence: 51%

Section: Energy Loss Of a Blinking Point Charge Close To The Gramentioning

confidence: 84%

Ab initiostudy of energy loss and wake potential in the vicinity of a graphene monolayer

et al. 2012

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“…For example, the π plasmon dispersion in graphene and carbon nanotubes splits if Q is in the → M direction but does not split if it is in the → K direction. [37][38][39] This means we should average Q over the high symmetry directions.…”

Section: Methodsmentioning

confidence: 99%

TDDFT study of time-dependent and static screening in graphene

et al. 2012

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Time-dependent density functional theory (TDDFT) within the random phase approximation (RPA) is used to obtain the time evolution of the induced potential produce by the sudden formation of a C 1s core hole inside a graphene monolayer, and to show how the system reaches the equilibrium potential. The characteristic oscillations in the time-dependent screening potential are related to the excitations of π and σ + π plasmons as well as the low energy 2D plasmons in doped graphene. The equilibrium RPA screened potential is compared with the DFT effective potential, yielding good qualitative agreement. The self energy of a point charge near a graphene monolayer is shown to demonstrate an image potential type behavior, Ze/(z − z 0 ), down to very short distances (4 a.u.) above the graphene layer. Both results are found to agree near quantitatively with the DFT ground state energy shift of a Li + ion placed near a graphene monolayer.

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“…31. A comparison between the experimental 14 and the theoretical spectrum obtained from expression (19) is shown in Fig.…”

Section: -5mentioning

confidence: 98%

“…The disadvantage of this method is that the calculation of the interacting electron response function χ of an isolated supercell is not straightforward because of the interaction between the supercells. Because of that, it is necessary to minimize or avoid the interaction between the supercells, e.g., by using a truncated bare Coulomb propagator, 30 or by using a "zero padding" method, 31 or simply by using a very large unit cell parameter L in the z direction. On the other hand, the supercell method has an advantage that the calculation can be carried out entirely in the reciprocal space.…”

Section: B Response Function Calculationmentioning

confidence: 99%

Two-dimensional andπplasmon spectra in pristine and doped graphene

et al. 2013

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The spectra of electronic excitations in graphene are calculated using first principles time-dependent density functional theory formalism, and used to obtain π and π + σ plasmon dispersion curves. The spectra and dispersion are in excellent agreement with recent experimental results, and they are used to investigate the anisotropy and splitting of a π plasmon, which has also been experimentally verified. The high accuracy of this calculation enabled the discovery of some different features in the spectra, especially the M-K anisotropy of the two-dimensional (2D) plasmon dispersion curve, which qualitatively agrees with recent experimental results. Our ab initio 2D plasmon dispersion curves are compared with the ones obtained in some recently proposed 2D models. They show strong disagreement with the dispersion curve obtained using a simple one-band 2D theory, as well as some discrepancies with respect to the commonly used Das Sarma et al.'s dispersion curve, even in the isotropic region. Excellent agreement of the calculated spectrum in pristine graphene with the electron energy loss spectroscopy spectrum measured for lower momentum transfers is demonstrated.

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Computing C1<I>s</I> X-ray Absorption for Single-Walled Carbon Nanotubes with Distinct Electronic Type

Cited by 11 publications

References 22 publications

Ab initiostudy of energy loss and wake potential in the vicinity of a graphene monolayer

Ab initiostudy of energy loss and wake potential in the vicinity of a graphene monolayer

TDDFT study of time-dependent and static screening in graphene

Two-dimensional andπplasmon spectra in pristine and doped graphene

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