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 $T_A$ 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. B 62, 10 950 (2000)] for the temperature dependence of the anomalous conductance plateau near ${0.7(2e}^2/h)$ in a quantum point contact.