Crossed Andreev Reflection in InSb Flake Josephson Junctions

• Published in: arXiv.org
• Main Authors: de Vries, Folkert K, Sol, Martijn L, Gazibegovic, Sasa, Roy L M op het Veld, Balk, Stijn C, Car, Diana, Erik P A M Bakkers, Kouwenhoven, Leo P, Shen, Jie
• Format: Paper Journal Article
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 14.06.2019
• Subjects: Cooper pairs; Entanglement; Flakes; Indium antimonide; Interference; Intermetallic compounds; Josephson junctions; Measuring instruments; Periodic variations; Physics - Mesoscale and Nanoscale Physics; Physics - Superconductivity; Reflection; Superconducting quantum interference devices; Superconductivity
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1906.05759

We study superconducting quantum interference in InSb flake Josephson junctions. An even-odd effect in the amplitude and periodicity of the superconducting quantum interference pattern is found. Interestingly, the occurrence of this pattern coincides with enhanced conduction at both edges of the flake, as is deduced from measuring a SQUID pattern at reduced gate voltages. We identify the specific crystal facet of the edge with enhanced conduction, and confirm this by measuring multiple devices. Furthermore, we argue the even-odd effect is due to crossed Andreev reflection, a process where a Cooper pair splits up over the two edges and recombines at the opposite contact. An entirely \(h/e\) periodic SQUID pattern, as well as the observation of both even-odd and odd-even effects, corroborates this conclusion. Crossed Andreev reflection could be harnessed for creating a topological state of matter or performing experiments on the non-local spin-entanglement of spatially separated Cooper pairs.