Photoconductivity calculations of bilayer graphene from first principles and deformation-potential approach

Abstract

We report first-principles calculations of electron-phonon coupling in bilayer graphene and the corresponding contribution to carrier scattering. At the phonon $\Gamma$ point, electrons with energies less than 200 meV are scattered predominantly by LA${}^{\prime }$ and TA${}^{\prime }$ modes while higher-energy electron scattering is dominated by optical phonon modes. Based on a two-temperature model, heat transfer from electrons with an initial temperature of 2000 K to the lattice (phonons) with an initial temperature of 300 K is computed, and in the overall relaxation process, most of this energy scatters into K-point phonon optical modes due to their strong coupling with electrons and their high energies. A Drude model is used to calculate photoconductivity for bilayer graphene with different doping levels. Good agreement with prior experimental trends for both the real and imaginary components of photoconductivity confirms the model's applicability. The effects of doping levels and electron-phonon scattering on photoconductiviy are analyzed. We also extract acoustic and optical deformation potentials from average scattering rates obtained from density functional theory (DFT) calculations and compare associated photoconductivity calculations with DFT results. The comparison indicates that momentum-dependent electron-phonon scattering potentials are required to provide accurate predictions.

References in corpus (15)

• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• Phonons and related properties of extended systems from density-functional perturbation theory
• Graphene Photonics and Optoelectronics
• EPW: Electron-phonon coupling, transport and superconducting properties using maximally localized Wannier functions
• Acoustic phonon scattering limited carrier mobility in 2D extrinsic graphene
• Ultrafast Optical-Pump Terahertz-Probe Spectroscopy of the Carrier Relaxation and Recombination Dynamics in Epitaxial Graphene
• Photo-excitation Cascade and Multiple Carrier Generation in Graphene
• Electron-phonon heat transfer in monolayer and bilayer graphene
• Unified description of the dc conductivity of monolayer and bilayer graphene at finite densities based on resonant scatterers
• Electron-Phonon Interactions in Graphene, Bilayer Graphene, and Graphite
• Semiconducting-to-metallic photoconductivity crossover and temperature-dependent Drude weight in graphene
• Unraveling the acoustic electron-phonon interaction in graphene
• Boltzmann transport and residual conductivity in bilayer graphene
• Cooling of photoexcited carriers in graphene by internal and substrate phonons
• Carrier Heating and Negative Photoconductivity in Graphene

Cited by in corpus (2)

• Electrically Tunable Interband Collective Excitations in Biased Bilayer and Trilayer Graphene
• Inelastic scattering and cooling of photoexcited electrons through coupling with acoustic, optic and surface polar optic phonons in graphene