Negative and positive magnetoresistance in bilayer graphene: Effects of weak localization and charge inhomogeneity

Yung Fu Chen, Myung Ho Bae, Cesar Chialvo, Travis Dirks, Alexey Bezryadin, Nadya Mason

Research output: Contribution to journalArticle

Abstract

We report measurements of magnetoresistance in bilayer graphene as a function of gate voltage (carrier density) and temperature. We examine multiple contributions to the magnetoresistance, including those of weak localization (WL), universal conductance fluctuations (UCF), and inhomogeneous charge transport. A clear WL signal is evident at all measured gate voltages (in the hole doped regime) and temperature ranges (from 0.25 to 4.3 K), and the phase coherence length extracted from the WL data does not saturate at low temperatures. The WL data is fit to demonstrate that the electronelectron Nyquist scattering is the major source of phase decoherence. A decrease in UCF amplitude with increase in gate voltage and temperature is shown to be consistent with a corresponding decrease in the phase coherence length. In addition, a weak positive magnetoresistance at higher magnetic fields is observed, and attributed to inhomogeneous charge transport.

Original languageEnglish (US)
Pages (from-to)785-788
Number of pages4
JournalPhysica B: Condensed Matter
Volume406
Issue number4
DOIs
StatePublished - Feb 1 2011

Keywords

  • Bilayer graphene
  • Localization
  • Magnetoresistance

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering

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