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Is the Peak Value of $σ_{xx}$ at the Quantum Hall Transition Universal?

K. Ziegler·G. Jug
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Abstract

The question of the universality of the longitudinal peak conductivity at the integer quantum Hall transition is considered. For this purpose, a system of 2D Dirac fermions with random mass characterised by variance $g$ is proposed as a model which undergoes a quantum Hall transition. Whilst for some specific models the longitudinal peak conductivity $σ_{xx}$ was found to be universal (in agreement with the conjecture of Lee et al. as well as with some numerical work), we find that $σ_{xx}$ is reduced by a factor $(1+g/2π)^{-1}$, at least for small $g$. This provides some theoretical evidence for the non-universality of $σ_{xx}$, as observed in a number of experiments.

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K. Ziegler, G. Jug. 1997-04-22. Is the Peak Value of $σ_{xx}$ at the Quantum Hall Transition Universal?. https://doi.org/10.1007/s002570050412

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