Carrier-carrier scattering and negative dynamic conductivity in pumped graphene

Abstract

We theoretically examine the effect of carrier-carrier scattering processes (electron-hole and electron-electron) on the intraband radiation absorption and their contribution to the net dynamic conductivity in optically or electrically pumped graphene. We demonstrate that the radiation absorption assisted by the carrier-carrier scattering can be stronger than the Drude absorption due to the carrier scattering on disorder. Since the intraband absorption of radiation effectively competes with its interband amplification, this can substantially affect the conditions of the negative dynamic conductivity in the pumped graphene and, hence, the interband terahertz and infrared lasing. We find the threshold values of the frequency and quasi-Fermi energy of nonequilibrium carriers corresponding to the onset of negative dynamic conductivity. The obtained results show that the effect of carrier-carrier scattering shifts the threshold frequency of the radiation amplification in pumped graphene to higher values. In particular, the negative dynamic conductivity is attainable at the frequencies above 6 THz in graphene on SiO2 substrates at room temperature. The threshold frequency can be decreased to markedly lower values in graphene structures with high-k substrates due to screening of the carrier-carrier scattering, particularly at lower temperatures.

arXiv comment14 pages, 7 figures

References in corpus (18)

• Graphene Photonics and Optoelectronics
• Measurement of the Optical Conductivity of Graphene
• Dielectric function, screening, and plasmons in 2D graphene
• Electron-Electron Interactions in Graphene: Current Status and Perspectives
• Optical far-infrared properties of graphene monolayer and multilayers
• Measurement of Ultrafast Carrier Dynamics in Epitaxial Graphene
• Ultrafast collinear scattering and carrier multiplication in graphene
• Quantum critical transport in clean graphene
• Terahertz and Infrared Spectroscopy of Gated Large-Area Graphene
• Conductivity of the defectless Graphene
• Voltage and temperature dependencies of conductivity in gated graphene
• Toward the creation of terahertz graphene injection laser
• Hydrodynamic model for electron-hole plasma in graphene
• Anisotropy of excitation and relaxation of photogenerated Dirac electrons in graphene
• Coulomb interaction in graphene: Relaxation rates and transport
• Threshold of Terahertz Population Inversion and Negative Dynamic Conductivity in Graphene Under Pulse Photoexcitation
• Towards loss compensated and lasing terahertz metamaterials based on optically pumped graphene
• Interplay of intra- and interband absorption in a disordered graphene

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• S-shaped current-voltage characteristics of n+-i-n-n+ graphene field-effect transistors due the Coulomb drag of quasi-equilibrium electrons by ballistic electrons
• Excitonic instability in optically-pumped three-dimensional Dirac materials
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• Generalized Parametric Space, Parity Symmetry of Reflection, and Systematic Design Approach for Parity-Time Symmetric Photonic Systems
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