Physical Review Letters
Print Issue of 4 November 2002

Phys. Rev. Lett. 89, 196802 (2002)

Kondo Model for the "0.7 Anomaly" in Transport through a Quantum Point Contact

Yigal Meir,1,2 Kenji Hirose,3 and Ned S. Wingreen1
1NEC Research Institute, 4 Independence Way, Princeton, New Jersey 08540
2Physics Department, Princeton University, Princeton, New Jersey 08540
3Fundamental Research Laboratories, NEC Corporation, 34 Miyukigaoka, Tsukuba, Ibaraki 305-8501, Japan

(Received 1 July 2002; published 21 October 2002)

Experimentson quantum point contacts have highlighted an anomalous conductance plateauaround 0.7(2e2/h), with features suggestive of the Kondo effect. Here, an Anderson model for transport through a point contact analyzed in the Kondo limit. Hybridization to the band increases abruptly with energy but decreases with valence, so that the background conductance and the Kondo temperature TK are dominated by different valence transitions. This accounts for the high residual conductance above TK. The model explains the observed gate-voltage, temperature, magnetic field, and bias-voltage dependences. A spin-polarized current is predicted even for low magnetic fields. ©2002 The American Physical Society

URL: http://link.aps.org/abstract/PRL/v89/e196802
doi:10.1103/PhysRevLett.89.196802
PACS: 73.61.-r, 71.15.Mb, 71.70.Ej, 75.75.+a

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References

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