Induced Superconducting Pairing in Integer Quantum Hall Edge States

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-Buttiker 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.

Automated summary

In this work, the results of InAs quantum wells placed near superconducting NbTiN are presented. Negative downstream resistance and reduction of Hall resistance indicate high efficiency Andreev conversion. Analysis of experimental data reveals that the high transparency of the InAs/NbTiN interface plays a crucial role in the efficient Andreev conversion.