Hatefipour Mehdi, Cuozzo Joseph J, Kanter Jesse, Strickland William M, Allemang Christopher R, Lu Tzu-Ming, Rossi Enrico, Shabani Javad
Center for Quantum Phenomena, Department of Physics, New York University, New York, New York 10003, United States.
Department of Physics, William & Mary, Williamsburg, Virginia 23187, United States.
Nano Lett. 2022 Aug 10;22(15):6173-6178. doi: 10.1021/acs.nanolett.2c01413. Epub 2022 Jul 22.
Indium arsenide (InAs) near surface quantum wells (QWs) are promising for the fabrication of semiconductor-superconductor heterostructures given that they allow for a strong hybridization between the two-dimensional states in the quantum well and the ones in the superconductor. In this work, we present results for InAs QWs in the quantum Hall regime placed in proximity of superconducting NbTiN. We observe a negative downstream resistance with a corresponding reduction of Hall (upstream) resistance, consistent with a very high Andreev conversion. We analyze the experimental data using the Landauer-Büttiker formalism, generalized to allow for Andreev reflection processes. We attribute the high efficiency of Andreev conversion in our devices to the large transparency of the InAs/NbTiN interface and the consequent strong hybridization of the QH edge modes with the states in the superconductor.
鉴于砷化铟（InAs）近表面量子阱（QWs）能够使量子阱中的二维态与超导体中的二维态实现强杂化，因此有望用于制造半导体 - 超导体异质结构。在这项工作中，我们展示了处于量子霍尔 regime 且靠近超导 NbTiN 的 InAs 量子阱的相关结果。我们观察到下游电阻为负，同时霍尔（上游）电阻相应降低，这与非常高的安德列夫转换相一致。我们使用朗道尔 - 比蒂克形式理论对实验数据进行分析，并对其进行了推广以考虑安德列夫反射过程。我们将器件中安德列夫转换的高效率归因于 InAs/NbTiN 界面的高透明度以及由此导致的量子霍尔边缘模式与超导体中态的强杂化。
