Conductance Anomalies in Quantum Point Contacts

We present a study of the conductance of quantum point contacts fabricated in AlGaN/GaN and Si/SiGe heterostructures. The investigated devices differ for typology (split gates and etched devices, respectively) and for the resulting potential profiles. We observe conductance quantization in multiple of 2e(2)/h units with superimposed anomalous plateaus and/or structures suggesting that correlation effects should be included in the description of our 1D systems.