Electron transport through quantum wires and point contacts

[摘要] We have studied quantum wires using the Green's function technique within density-functional theory, calculating electronic structures and conductances for different wire lengths, temperatures, and bias voltages. For short wires, i.e., quantum point contacts, the zero-bias conductance shows as a function of the gate voltage and at a finite temperature a plateau at around 0.7G(0). (G(0)=2e(2)/h is the quantum conductance.) The behavior, which is caused in our mean-field model by spontaneous spin polarization in the constriction, is reminiscent of the so-called 0.7 anomaly observed in experiments. In our model the temperature and the wire length affect the conductance-gate-voltage curves similarly as in experiments.

[发布日期] 2004-12-01

[关键词] CONDUCTANCE