Temperature Dependent Suppression of Conductance in Quantum Wires: Anomalous Activation Energy from Pinning of the Band Edge

For unpolarized electrons in a clean quantum wire, density functional theory reveals a thermally activated suppression of conductance. The activation temperature TA grows slowly (roughly quadratically) with gate voltage due to pinning of the band edge at the chemical potential. Similar results were obtained experimentally by Kristensen et al. [Phys. Rev. B62, 10950 (2000)] for the temperature dependence of the anomalous conductance plateau near 0.7 (2e/h) in a quantum point contact.