Title:  Zero-bias anomalies in hybrid superconductor-semiconductor nanowire devices
Abstract:
Zero-bias anomalies in hybrid superconductor-semiconductor nanowire devices
E. J. H. Lee1*, X. Jiang2, G. Katsaros1, M. Houzet1, R. Aguado3, C. M. Lieber2 and S. De Franceschi1
1 SPSMS, CEA-INAC/UJF-Grenoble 1, 17 rue des Martyrs, 38054, Grenoble, France
2 Harvard University, Department of Chemistry and Chemical Biology, Cambridge, MA, 02138, USA
3 Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), Cantoblanco, 28049, Madrid, Spain
* current address: Institut Neel, CNRS,  25 rue des Martyrs, 38042, Grenoble, France

Hybrid devices that couple superconductors to semiconductor nanowires with strong spin-orbit interaction have been proposed as a promising platform for the realization of Majorana bound states (MBSs) [1,2]. Experimental efforts in this direction have focused on tunnel spectroscopy measurements aimed at the detection of the zero-energy Majorana modes. In this approach, the main sought-after signature is a zero-bias peak (ZBP) in the tunneling conductance, which is expected to emerge at finite magnetic field and to be robust against gate voltage and magnetic field variations. ZBPs of this kind have been recently reported [3-7]. However, in order to unambiguously assign these ZBPs to MBSs, it is important to rule out other physical mechanisms that yield similar zero-bias anomalies. In this work, we carefully study two of these alternative mechanisms in hybrid devices based on InAs/InP core/shell nanowires. Specifically, we address ZBPs emerging from the Zeeman-induced crossing of Andreev levels at the Fermi energy [8], and from the Kondo effect resulting from sub-gap states in the superconducting leads [9].

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