Effective numbers of charge carriers in doped graphene: Generalized Fermi liquid approach

Scientific paper - Original scientific paper

• Author: Ivan Kupčić; MBZ: 172534
• Author: Goran Nikšić; MBZ: 320900
• Author: Zoran Rukelj; MBZ: 330912
• Author: Damjan Pelc; MBZ: 334826
• Author's institution: University of Zagreb; Faculty of Science; (Department of Physics)
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Physics

Abstract (english)

The single-band current-dipole Kubo formula for the dynamical conductivity of heavily doped graphene from Kupčić [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 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 the dc conductivity 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 the dc conductivity 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.

• Keywords (english): quantum transport equations; lightly doped graphene; dc and optical conductivity; energy loss spectroscopy
• Language: english
• Publication type: Scientific paper - Original scientific paper
• Publication status: Published
• Peer review: Peer review - international
• Publication version: Published version
• Journal title: Physical Review B
• Numbering: vol. 94, no. 7, 075434
• p-ISSN: 2469-9950
• DOI: https://doi.org/10.1103/PhysRevB.94.075434
• URN:NBN: urn:nbn:hr:217:686153
• Publication: 2016
• Project: Number: 119-1191458-0512; Title (croatian): Niskodimenzionalni jako korelirani vodljivi sustavi; Leader: Slaven Barišić; Jurisdiction: Croatia; Funding stream: ZP
• Document URL: https://journals.aps.org/prb/abstract/10.1103/PhysRevB.94.075434
• Type of resource: Text
• Access conditions: Open access
• Public note: © 2016 American Physical Society. Received 6 April 2016; revised manuscript received 2 July 2016; published 23 August 2016.
• Created on: 2020-02-23 19:17:51