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Dissipative quantum hall effect in graphene near the Dirac point
Dmitry A Abanin1, Kostya S Novoselov, Uli Zeitler
1Department of Physics, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA 02139, USA.
Physical Review Letters
|August 7, 2007
Summary
In graphene, the integer quantum Hall effect
Area of Science:
- Condensed Matter Physics
- Materials Science
Background:
- The integer quantum Hall effect (QHE) is a key phenomenon in condensed matter physics.
- Graphene's unique electronic properties, including massless Dirac quasiparticles, lead to distinct QHE behaviors.
Purpose of the Study:
- To investigate the unusual nu=0 state in graphene's integer quantum Hall effect.
- To elucidate the dominant transport mechanisms and characteristics of this state.
Main Methods:
- Experimental measurements of longitudinal resistivity (rho(xx)) and Hall resistivity (rho(xy)).
- Analysis of conductivity (sigma(xy)) to understand edge state contributions.
Main Results:
- Electron transport is dominated by counterpropagating edge states at nu=0.
- Observed large longitudinal resistivity (rho(xx) > h/e^2), contrasting with standard QHE.
- Detected pronounced fluctuations in rho(xy) and rho(xx), and a smeared zero Hall plateau in sigma(xy).
Conclusions:
- The nu=0 state in graphene is characterized by gapless edge states.
- These findings challenge existing theoretical models for the QHE in graphene.
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