Zero-bias anomaly in quantum wires

We use quantum wires fabricated on undoped GaAs/AlGaAs heterostructures in which the average impurity separation is greater than the device size to compare the behavior of the zero-bias anomaly against predictions from Kondo and spin-polarization models. Both theories display shortcomings, the most dramatic of which is the linear electron-density dependence of the zero-bias anomaly spin splitting at fixed magnetic field B and the suppression of the Zeeman effect at pinch off.