Chiral surface states in the bulk quantum Hall effect

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 filing nu = 1/3, the sheath is a 2D non-Fermi-liquid, with incoherent z-axis transport and sigma(zz) similar to T-3. Experimental implications for the Bechgaard salts are discussed.