Epitaxially Driven Phase Selectivity of Sn in Hybrid Quantum Nanowires

• Published in: arXiv.org
• Main Authors: Khan, Sabbir A, Martí-Sánchez, Sara, Olsteins, Dags, Lampadaris, Charalampos, Damon James Carrad, Liu, Yu, Quiñones, Judith, Spadaro, Maria Chiara, Jespersen, Thomas S, Krogstrup, Peter, Arbiol, Jordi
• Format: Paper
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 02.01.2023
• Subjects: Crystal structure; Heterostructures; Indium antimonide; Indium arsenides; Intermetallic compounds; Nanowires; Optimization; Phase control; Selectivity; Superconductivity; Thickness; Topology
• ISSN: 2331-8422

Hybrid semiconductor/superconductor nanowires constitute a pervasive platform for studying gate-tunable superconductivity and the emergence of topological behavior. Their low-dimensionality and crystal structure flexibility facilitate novel heterostructure growth and efficient material optimization; crucial prerequisites for accurately constructing complex multi-component quantum materials. Here, we present an extensive optimization of Sn growth on InSb, InAsSb and InAs nanowires. We demonstrate how the growth conditions and the crystal structure/symmetry of the semiconductor drive the formation of either semi-metallic \(\mathrm{\alpha-Sn}\) or superconducting \(\mathrm{\beta-Sn}\). For InAs nanowires, we obtain phase-pure, superconducting \(\mathrm{\beta-Sn}\) shells. However, for InSb and InAsSb nanowires, an initial epitaxial \(\mathrm{\alpha-Sn}\) phase evolves into a polycrystalline shell of coexisting \(\mathrm{\alpha}\) and \(\mathrm{\beta}\) phases, where the \(\beta/\alpha\) volume ratio increases with Sn shell thickness. Whether these nanowires exhibit superconductivity or not critically relies on the \(\mathrm{\beta-Sn}\) content. Therefore, this work provides key insights into Sn phase control on a variety of semiconductors, with consequences for the yield of superconducting hybrids suitable for generating topological systems.