Chiral Surface States in the Bulk Quantum Hall Effect

TL;DR

This paper investigates the surface states in layered quantum Hall systems, revealing a chiral 2D quantum liquid with unique transport properties, including metallic and non-Fermi liquid behaviors, with implications for experimental observations.

Contribution

It demonstrates the existence of a chiral surface sheath in bulk quantum Hall systems and characterizes its transport properties for integer and fractional fillings.

Findings

Integer QHE sheath exhibits metallic z-axis conductivity.

Fractional filling ν=1/3 sheath shows incoherent transport with σ_{zz} ∼ T^3.

Implications discussed for Bechgaard salts experiments.

Abstract

In layered samples which exhibit a bulk quantum Hall effect (QHE), a two-dimensional (2d) surface ``sheath" of gapless excitations is expected. These excitations comprise a novel 2d chiral quantum liquid which should dominate the low temperature transport along the field (z-axis). For the integer QHE, we show that localization effects are completely absent in the ``sheath", giving a metallic z-axis conductivity. For fractional filling $\nu =1/3$, the ``sheath" is a 2d non-Fermi liquid, with incoherent z-axis transport and $\sigma_{zz} \sim T^3$. Experimental implications for the Bechgaard salts are discussed.