Control over epitaxy and the role of the InAs/Al interface in hybrid two-dimensional electron gas systems
Erik Cheah, Daniel Z. Haxell, Rüdiger Schott, Peng Zeng, Ekaterina Paysen, Sofieke C. ten Kate, Marco Coraiola, Max Landstetter, Ali Baghi Zadeh, A. Trampert, Marilyne Sousa, Heike Riel, Fabrizio Nichele, W. Wegscheider, Filip Křížek
Abstract
The interface quality in semiconductor/superconductor (SE/SC) platforms plays a crucial role for the superconducting coupling strength. In this work, a novel growth approach to grow grain-boundary-free Al on a lattice-mismatched InAs quantum well is introduced. More specifically, a monocrystalline Al phase is achieved by intentional roughening of the semiconductor surface. This approach can in general be applied to other mismatched material systems where a high degree of crystallinity is essential. Furthermore, the authors investigate the altered interfaces in transport measurements, hoping to shed more light upon the pressing question: ``What is the role of the detailed crystallography of the SC for the performance of SE/SC hybrid devices?''