Carrier dynamics in Landau-quantized graphene featuring strong Auger scattering

Mittendorff, Martin; Wendler, Florian; Malić, Ermin; Knorr, Andreas; Орлита, М.; Potemski, M.; Berger, Claire; Heer, Walter A. de; Schneider, Harald; Helm, M.; Winnerl, Stephan

doi:10.1038/nphys3164

Cited by 93 publications

(105 citation statements)

References 48 publications

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“…In previous studies, a significant carrier multiplication has been predicted in optically excited graphene [2][3][4] as well as Landau-quantized graphene [5]. Meanwhile carrier multiplication has also been demonstrated in time-dependent ARPES measurements [6] as well as in high-resolution pumpprobe studies [7][8][9]. In doped graphene samples, a so-called hot CM has been theoretically predicted [10] and experimentally measured [11,12].…”

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confidence: 87%

Experimentally accessible signatures of Auger scattering in graphene

2016

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The gapless and linear electronic band structure of graphene opens up Auger scattering channels bridging the valence and the conduction band and changing the charge carrier density. Here, we reveal experimentally accessible signatures of Auger scattering in optically excited graphene. To be able to focus on signatures of Auger scattering, we apply a low excitation energy, weak pump fluences, and a cryostatic temperature, so that all relevant processes lie energetically below the optical phonon threshold. In this regime, carrier-phonon scattering is strongly suppressed and Coulomb processes govern the carrier dynamics. Depending on the excitation regime, we find an accumulation or depletion of the carrier occupation close to the Dirac point. This reflects well the behavior predicted from Auger-dominated carrier dynamics. Based on this observation, we propose a multicolor pump-probe experiment to uncover the extreme importance of Auger channels for the nonequilibrium dynamics in graphene.

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confidence: 87%

Experimentally accessible signatures of Auger scattering in graphene

2016

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“…The availability of extremely intense, spectrally tunable coherent light pulses facilitates progress in various scientific fields due to the possibility to perform optical spectroscopy [1] and imaging [2,3] of matter on its natural time and length scales. The concept of the free-electron laser allows to generate ultrafast optical pulses from the THz to the hard x-ray regime, determined solely by the electron bunch length and energy.…”

Section: Introductionmentioning

confidence: 99%

Femtosecond single-shot timing and direct observation of subpulse formation in an infrared free-electron laser

Kiessling

Colson

Gewinner

et al. 2018

Phys. Rev. Accel. Beams

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We experimentally demonstrate a single-shot arrival time monitor for short picosecond infrared freeelectron laser (IR FEL) pulses based on balanced optical cross-correlation with a synchronized fs table-top laser. Employing this timing tool at the Fritz Haber Institute IR FEL, we observe a shot-to-shot timing jitter of only 100 fs and minute-scale timing drifts of a few picoseconds, the latter being strictly correlated with the electron beam energy of the accelerator. We acquire sum-frequency cross-correlation data with micropulse resolution, providing full access to the IR FEL pulse shape evolution within the macropulse. These measurements provide unprecedented insights into the occurrence of limit-cycle oscillations of the FEL intensity as a consequence of subpulse formation. Our experimental results are complemented by fourdimensional simulations of the nonlinear pulse dynamics in a low-gain FEL oscillator based on MaxwellLorentz theory.

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“…Since the optical phonon energies are much larger than the low-energy photons [15], the phononinduced relaxation should be also negligible [6]. However, to account for the rather fast experimentally observed decay of differential transmission [13,14], carrier-phonon scattering is included on a phenomenological level.…”

Section: A Semiconductor Bloch Equationsmentioning

confidence: 99%

“…As described in Ref. [13], E F in Landau-quantized graphene is extracted from the Fermi energy in the absence of a magnetic field using the assumption that the carrier concentration does not change when a magnetic field is switched on.…”

Section: A Semiconductor Bloch Equationsmentioning

confidence: 99%

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Doping-dependent intraband carrier dynamics in Landau-quantized graphene

Wendler

Malić

2016

Phys. Rev. B

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We investigate the intraband carrier dynamics in Landau-quantized graphene after an optical excitation with low-energetic terahertz pulses. Based on a microscopic theory, we calculate time-dependent differential transmission spectra reflecting the Landau-level dynamics. Our calculations reveal a strong dependence on the Fermi energy E F of the graphene sample as well as on the applied magnetic field B. We find that the pump pulse can lead to both absorption bleaching and absorption enhancement depending on B and the position of E F with respect to the resonant Landau-level transition. As a result, positive and negative contributions in differential transmission spectra appear, in good agreement with recent pump-probe measurements.

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Carrier dynamics in Landau-quantized graphene featuring strong Auger scattering

Abstract: International audienc

Cited by 93 publications

References 48 publications

Experimentally accessible signatures of Auger scattering in graphene

Experimentally accessible signatures of Auger scattering in graphene

Femtosecond single-shot timing and direct observation of subpulse formation in an infrared free-electron laser

Doping-dependent intraband carrier dynamics in Landau-quantized graphene

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