Electron correlations and the conductance of a quantum point contact at finite temperature
To describe electron transport through a quantum point contact we formulate and solve a nonlocal kinetic equation for the density matrix of electrons. The electron-electron interaction is treated by perturbation theory with account of higher order terms. At zero temperature, the approach results in the Landauer formula for conductance of a quantum point contact. At finite temperature, the leading correction to the current of correlated electrons scales as temperature squared. The corresponding correction to conductance G is negative and strongly enhanced in the region 0.52e2h≤G≤1.02e2h. The effect may be relevant to the so called "0.7 structure" of conductance observed experimentally. © 2008 American Institute of Physics.