Ballistic Transport and Exchange Interaction in InAs Nanowire Quantum Point Contacts

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• 作者：S. Heedt ; W. Prost ; J. Schubert ; D. Grützmacher ; Th. Schäpers
• 刊名：Nano Letters
• 出版年：2016
• 出版时间：May 11, 2016
• 年：2016
• 卷：16
• 期：5
• 页码：3116-3123
• 全文大小：595K
• 年卷期：0
• ISSN：1530-6992

文摘

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 0.7·2e²/h conductance anomaly, commonly found in planar devices.