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Electron transport through quantum wires and point contacts

Paula Havu·Martti Puska·Risto Nieminen·Ville Havu
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Abstract

We have studied quantum wires using the Green's function technique and the density-functional theory, calculating the electronic structure and the conductance. All the numerics are implemented using the finite-element method with a high-order polynomial basis. 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 in the same way as in the measured data.

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Paula Havu, Martti Puska, Risto Nieminen, Ville Havu. 2004-06-07. Electron transport through quantum wires and point contacts. https://doi.org/10.1103/physrevb.70.233308

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