Thermal conductance of Nb thin films at sub-kelvin temperatures

A. V. Feshchenko*, O. P. Saira, Joonas Peltonen, J. P. Pekola

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

4 Citations (Scopus)
126 Downloads (Pure)

Abstract

We determine the thermal conductance of thin niobium (Nb) wires on a silica substrate in the temperature range of 0.1-0.6 K using electron thermometry based on normal metal-insulator-superconductor tunnel junctions. We find that at 0.6 K, the thermal conductance of Nb is two orders of magnitude lower than that of Al in the superconducting state, and two orders of magnitude below the Wiedemann-Franz conductance calculated with the normal state resistance of the wire. The measured thermal conductance exceeds the prediction of the Bardeen-Cooper-Schrieffer theory, and demonstrates a power law dependence on temperature as T4.5, instead of an exponential one. At the same time, we monitor the temperature profile of the substrate along the Nb wire to observe possible overheating of the phonon bath. We show that Nb can be successfully used for thermal insulation in a nanoscale circuit while simultaneously providing an electrical connection.

Original languageEnglish
Article number41728
Pages (from-to)1-13
JournalScientific Reports
Volume7
DOIs
Publication statusPublished - 3 Feb 2017
MoE publication typeA1 Journal article-refereed

Fingerprint Dive into the research topics of 'Thermal conductance of Nb thin films at sub-kelvin temperatures'. Together they form a unique fingerprint.

  • Projects

    Quantum technology and materials for parallel sensor-actuator units in ICT

    Pekola, J. & Saira, O.

    01/01/201531/12/2016

    Project: Academy of Finland: Other research funding

    Equipment

  • Cite this