Effective numbers of charge carriers in doped graphene: Generalized Fermi liquid approach
| Autor: | Damjan Pelc, Goran Nikšić, Zoran Rukelj, Ivan Kupčić |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: |
FOS: Physical sciences
02 engineering and technology Electron quantum transport equations lightly doped graphene dc and optical conductivity energy loss spectroscopy 01 natural sciences Optical conductivity law.invention law Kubo formula Mesoscale and Nanoscale Physics (cond-mat.mes-hall) 0103 physical sciences 010306 general physics Physics Condensed Matter - Mesoscale and Nanoscale Physics Condensed matter physics Graphene 021001 nanoscience & nanotechnology Thermal conduction NATURAL SCIENCES. Physics 3. Good health PRIRODNE ZNANOSTI. Fizika Quasiparticle Charge carrier Fermi liquid theory 0210 nano-technology |
| Zdroj: | Physical Review B Volume 94 Issue 7 |
| ISSN: | 2469-9950 |
| DOI: | 10.1103/physrevb.94.075434 |
| Popis: | The single-band current-dipole Kubo formula for the dynamical conductivity of heavily doped graphene from Kup\v{c}i\'{c} [Phys. Rev. B 91, 205428 (2015)] is extended to a two-band model for conduction $\pi$ electrons in lightly doped graphene. Using a posteriori relaxation-time approximation in the two-band quantum transport equations, with two different relaxation rates and one quasi-particle lifetime, we explain a seemingly inconsistent dependence of the dc conductivity $\sigma^{\rm dc}_{\alpha \alpha}$ of ultraclean and dirty lightly doped graphene samples on electron doping, in a way consistent with the charge continuity equation. It is also shown that the intraband contribution to the effective number of conduction electrons in $\sigma^{\rm dc}_{\alpha \alpha}$ vanishes at $T=0$ K in the ultraclean regime, but it remains finite in the dirty regime. The present model is shown to be consistent with a picture in which the intraband and interband contributions to $\sigma^{\rm dc}_{\alpha \alpha}$ are characterized by two different mobilities of conduction electrons, the values of which are well below the widely accepted value of mobility in ultraclean graphene. The dispersions of Dirac and $\pi$ plasmon resonances are reexamined to show that the present, relatively simple expression for the dynamical conductivity tensor can be used to study simultaneously single-particle excitations in the dc and optical conductivity and collective excitations in energy loss spectroscopy experiments. Comment: 13 pages, 11 figures |
| Databáze: | OpenAIRE |
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