Boundary-mediated electron-electron interactions in quantum point contacts

Vincent Thomas Francois Renard (1, 2) , O. A. Tkachenko (2, 3) , V.A. Tkachenko (3) , T. Ota (1) , N. Kumada (1) , J.-C. Portal (2, 4) , Y. Hirayama (1, 5, 6)

1 NTT, BRL - NTT BRL, NTT Corporation
2 LCMI-GHMFL - Laboratoire des champs magnétiques intenses
3 Institute of semiconductor Physics - Institute of semiconductor Physics
4 INSA Toulouse - Institut National des Sciences Appliquées - Toulouse
5 SORST-JST - SORST-JST
6 Tohoku University - Department of Physics, Tohoku University

An unusual increase of the conductance with temperature is observed in clean quantum point contacts for conductances larger than 2e^2/h. At the same time a positive magnetoresistance arises at high temperatures. A model accounting for electron-electron interactions mediated by bound- aries (scattering on Friedel oscillations) qualitatively describes the observation. It is supported by numerical simulation at zero magnetic field.

Domaines: Systèmes mésoscopiques et effet Hall quantique [cond-mat.mes-hall]

Vincent Thomas Francois Renard, O. A. Tkachenko, V.A. Tkachenko, T. Ota, N. Kumada, et al.. Boundary-mediated electron-electron interactions in quantum point contacts. Physical Review Letters, 2008, 100, pp.186801. ⟨10.1103/PhysRevLett.100.186801⟩. ⟨hal-00266529v2⟩