Improved Nb SIS devices for heterodyne mixers between 700 GHz and 1.3 THz with NbTiN transmission lines using a normal metal energy relaxation layer
Abstract
In this paper, we demonstrate experimentally the implementation of a niobium-trilayer junction with an aluminum-oxide tunnel barrier, embedded in a high-gap superconducting niobium-titanium-nitride circuit. Previously reported heating by quasiparticle trapping is removed by inserting a normal metal layer of gold between the niobium junction and the niobium-titanium-nitride layer. We analyze in dc-characterization measurements the cooling of the nonequilibrium quasiparticles in various device geometries having different gold layer thickness and shape. Our work is concluded with remarks for future heterodyne mixer experiments using our device technology.
- Publication:
-
Journal of Applied Physics
- Pub Date:
- September 2013
- DOI:
- 10.1063/1.4822167
- arXiv:
- arXiv:1306.6797
- Bibcode:
- 2013JAP...114l4504W
- Keywords:
-
- alumina;
- cooling;
- gold;
- niobium compounds;
- quasiparticles;
- superconducting transmission lines;
- superconductor-insulator-superconductor mixers;
- titanium compounds;
- 85.25.Cp;
- 84.30.Qi;
- 84.40.Az;
- Josephson devices;
- Modulators and demodulators;
- discriminators comparators mixers limiters and compressors;
- Waveguides transmission lines striplines;
- Condensed Matter - Mesoscale and Nanoscale Physics
- E-Print:
- 11 pages, 6 figures, 4 tables