Ballistic Transport and Exchange Interaction in InAs Nanowire Quantum Point Contacts.
One-dimensional ballistic transport is demonstrated for a high-mobility InAs nanowire device. Unlike conventional quantum point contacts (QPCs) created in a two-dimensional electron gas, the nanowire QPCs represent one-dimensional constrictions formed inside a quasi-one-dimensional conductor. For each QPC, the local subband occupation can be controlled individually between zero and up to six degenerate modes. At large out-of-plane magnetic fields Landau quantization and Zeeman splitting emerge and comprehensive voltage bias spectroscopy is performed. Confinement-induced quenching of the orbital motion gives rise to significantly modified subband-dependent Landé g factors. A pronounced g factor enhancement related to Coulomb exchange interaction is reported. Many-body effects of that kind also manifest in the observation of the 0.7·2e(2)/h conductance anomaly, commonly found in planar devices.
Peter Grünberg Institut (PGI-9) and JARA-Fundamentals of Future Information Technology, Forschungszentrum Jülich , 52425 Jülich, Germany.
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S
Heedt
Solid State Electronics Department, University of Duisburg-Essen , 47057 Duisburg, Germany.
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W
Prost
Peter Grünberg Institut (PGI-9) and JARA-Fundamentals of Future Information Technology, Forschungszentrum Jülich , 52425 Jülich, Germany.
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J
Schubert
Peter Grünberg Institut (PGI-9) and JARA-Fundamentals of Future Information Technology, Forschungszentrum Jülich , 52425 Jülich, Germany.
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D
Grützmacher
Peter Grünberg Institut (PGI-9) and JARA-Fundamentals of Future Information Technology, Forschungszentrum Jülich , 52425 Jülich, Germany.
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Schäpers
0.7·2e2/h anomaly; Ballistic transport; InAs nanowire; exchange interaction; g factors; quantum point contacts