Hybrid superinductance with Al/InAs

Abstract

We report microwave spectroscopy of Josephson junctions chains made from an epitaxial Al/InAs heterostructure. The chains exhibit superinductance, with characteristic wave impedance exceeding $R_Q=\hslash /(2e{)}^2$. The planar nature of the junctions results in a large plasma frequency, with no measurable deviations from ideal dispersion up to $12\mathrm{GHz}$. Internal quality factors decrease sharply with frequency, which we describe with a simple loss model. The possibility of a loss mechanism intrinsic to the superconductor-semiconductor junction is considered.

6 pages, 4 figures