Dynamic polarization of graphene by moving external charges: Random phase approximation
Autor: | Kyle Allison, Ivan Radović, Duško Borka, Zoran L. Mišković, Lj. Hadžievski |
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Rok vydání: | 2009 |
Předmět: |
FOS: Physical sciences
02 engineering and technology electron energy loss spectra Electrochemistry 01 natural sciences 7. Clean energy law.invention RPA calculations law 0103 physical sciences dynamic nuclear polarisation 010306 general physics dielectric function Physics Condensed Matter - Materials Science Condensed matter physics Graphene Electron energy loss spectroscopy Doping graphene Materials Science (cond-mat.mtrl-sci) 021001 nanoscience & nanotechnology Condensed Matter Physics Polarization (waves) carrier density Charged particle Electronic Optical and Magnetic Materials electrochemistry Kinetic equations Quantum Gases (cond-mat.quant-gas) 0210 nano-technology Random phase approximation Condensed Matter - Quantum Gases |
Zdroj: | Physical Review B: Condensed Matter and Materials Physics |
Popis: | We evaluate the stopping and image forces on a charged particle moving parallel to a doped sheet of graphene by using the dielectric response formalism for graphene's $\pi$-electron bands in the random phase approximation (RPA). The forces are presented as functions of the particle speed and the particle distance for a broad range of charge-carrier densities in graphene. A detailed comparison with the results from a kinetic equation model reveal the importance of inter-band single-particle excitations in the RPA model for high particle speeds. We also consider the effects of a finite gap between graphene and a supporting substrate, as well as the effects of a finite damping rate that is included through the use of Mermin's procedure. The damping rate is estimated from a tentative comparison of the Mermin loss function with a HREELS experiment. In the limit of low particle speeds, several analytical results are obtained for the friction coefficient that show an intricate relationship between the charge-carrier density, the damping rate, and the particle distance, which may be relevant to surface processes and electrochemistry involving graphene. Comment: 14 pages, 10 figures, accepted for publication in Phys. Rev. B |
Databáze: | OpenAIRE |
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