Silver-epoxy microwave filters and thermalizers for millikelvin experiments

• Published in: Applied physics letters Vol. 104; no. 21
• Main Authors: Scheller, Christian P., Heizmann, Sarah, Bedner, Kristine, Giss, Dominic, Meschke, Matthias, Zumbühl, Dominik M., Zimmerman, Jeramy D., Gossard, Arthur C.
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 26-05-2014
• Subjects: Applied physics; ATTENUATION; CAPACITORS; CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; Electron energy; ELECTRON TEMPERATURE; EPOXIDES; FILTERS; Filtration; GALLIUM ARSENIDES; MHZ RANGE; Microwave attenuation; Microwave filters; MICROWAVE RADIATION; QUANTUM DOTS; Quantum transport; Sample holders; SILVER; TEMPERATURE RANGE 0000-0013 K; THERMALIZATION; Thermalization (energy absorption); THERMOMETERS
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.4880099

We present silver-epoxy filters combining excellent microwave attenuation with efficient wire thermalization, suitable for low temperature quantum transport experiments. Upon minimizing parasitic capacitances, the attenuation reaches ≥100 dB above ≈150 MHz and—when capacitors are added—already above ≈30 MHz. We measure the device electron temperature with a GaAs quantum dot and demonstrate excellent filter performance. Upon improving the sample holder and adding a second filtering stage, we obtain electron temperatures as low as 7.5 ± 0.2 mK in metallic Coulomb blockade thermometers.