Charge Rearrangement and Screening in a Quantum Point Contact
S. Lüscher,1 L. S. Moore,1 T. Rejec,2 Yigal Meir,2 Hadas Shtrikman,3 and D. Goldhaber-Gordon1
1Department of Physics, Stanford University, Stanford, California 94305, USA
2Department of Physics, Ben Gurion University of the Negev, Beersheva, Israel
3Submicron Center, Weizmann Institute of Science, Rehovot, Israel
(Received 20 April 2006; published 11 May 2007)
Compressibility measurements are performed on a quantum point contact (QPC). Screening due to mobile charges in the QPC is measured quantitatively, using a second point contact. These measurements are performed from pinch-off through the opening of the first few modes in the QPC. While the measured signal closely matches a Thomas-Fermi-Poisson prediction, deviations from the classical behavior are apparent near the openings of the different modes. Density functional calculations attribute the deviations to a combination of a diverging density of states at the opening of each one-dimensional mode and exchange interaction, which is strongest for the first mode.
©2007 The American Physical Society
PACS: 73.21.Hb, 73.23.-b, 73.43.Fj, 73.61.Ey
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Auxiliary Material (EPAPS)
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