Conductance fluctuations of chiral metals

We study conductance fluctuations of the edge-state sheath that forms in th e integer quantum Hall effect from the coupled edge states of a GaAs/AlxGa1 -xAs multilayer. Comparison of the measured variance in the vertical conduc tance to recent theoretical predictions for mesoscopic fluctuations suggest s dephasing lengths of 1-10 mu m around the sheath perimeter at low tempera tures. However, inconsistencies in the estimated inelastic lengths indicate that present understanding of dephasing on the sheath is incomplete. (C) 1 999 Academic Press.