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arXiv · 1608.02750

Electronic-structural Dynamics in Graphene

Isabella Gierz·Andrea Cavalleri
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Abstract

We review our recent time- and angle-resolved photoemission spectroscopy experiments, which measure the transient electronic structure of optically driven graphene. For pump photon energies in the near infrared ($\hbar\omega_{\text{pump}}=950$meV) we have discovered the formation of a population-inverted state near the Dirac point, which may be of interest for the design of THz lasing devices and optical amplifiers. At lower pump photon energies ($\hbar\omega_{\text{pump}}<400$meV), for which interband absorption is not possible in doped samples, we find evidence for free carrier absorption. In addition, when mid-infrared pulses are made resonant with an infrared-active in-plane phonon of bilayer graphene ($\hbar\omega_{\text{pump}}=200$meV), a transient enhancement of the electron-phonon coupling constant is observed, providing interesting perspective for experiments that report light-enhanced superconductivity in doped fullerites in which a similar lattice mode was excited. All the studies reviewed here have important implications for applications of graphene in optoelectronic devices and for the dynamical engineering of electronic properties with light.

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Isabella Gierz, Andrea Cavalleri. 2016-08-09. Electronic-structural Dynamics in Graphene. https://arxiv.org/abs/1608.02750

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