Europhys. Lett.
Volume 67, Number 4, August 2004
Page(s) 634 - 640
Section Condensed matter: electronic structure, electrical, magnetic, and optical properties
Published online 01 August 2004
Europhys. Lett., 67 (4), pp. 634-640 (2004)
DOI: 10.1209/epl/i2004-10090-0

On the magnetic nature of quantum point contacts

P. S. Cornaglia and C. A. Balseiro

Instituto Balseiro and Centro Atómico Bariloche Comisión Nacional de Energía Atómica 8400 San Carlos de Bariloche, Río Negro, Argentina

(Received 26 January 2004; accepted in final form 7 June 2004)

We present results for a model that describes a quantum point contact. We show how electron-electron correlations, within the unrestricted Hartree-Fock approximation, generate a magnetic moment in the point contact. Having characterized the magnetic structure of the contact, we map the problem onto a simple one-channel model and calculate the temperature dependence of the conductance for different gate voltages. Our results are in good agreement with experimental results obtained in $\chem{GaAs}$ devices and support the idea of Kondo effect in these systems.

73.23.-b - Electronic transport in mesoscopic systems.
75.75.+a - Magnetic properties of nanostructures.

© EDP Sciences 2004