The 0.7 structure in cleaved edge overgrowth wires

Abstract

We study the conductance through long and ultra-clean one-dimensional conductors andfind a conductance anomaly at low charge densities—similar to the so-called 0.7 structurefound in short constrictions. Our wires, afforded by the cleaved edge overgrowth technique,allow a quantitative study of this phenomenon in long wires. We find that this anomalyoccurs whenever the kinetic energy provided to the carriers exceeds the Fermi energy. Inthis regime, the measured conductance is found to exceed the value naively expected fromnon-interacting models.