TUNNELING THROUGH POINT CONTACTS IN THE QUANTUM HALL-EFFECT

We study tunneling through gated point contacts on GaAs/AlGaAs heteroj unctions in the regime of the integer (IQHE) and fractional (FQHE) qua ntum Hall effects. The off-resonant conductance data at bulk filling f actor v = 1/3 has a steep temperature dependence that is roughly consi stent with the predictions of Luttinger liquid theory for edge states. In the IQHE, we find only weak temperature dependence at v = 1 in the bulk. However, the line shape of tunneling resonances at v = 1 is not well fit by a Fermi-liquid form, perhaps indicating that complex edge structure affects resonant transmission. (C) 1998 Elsevier Science B. V. All rights reserved.