Thin-film nanostructuring of NbTi superconducting resonators for enhanced temperature sensitivity in cryogenic thermometry
Abstract
The rising complexity of cutting-edge cryogenic systems is currently imposing challenging technical constraints to the monitoring of ultra-cold temperatures through standard commercially available sensors. Among different technologies, superconducting microwave resonators have been recently investigated as ideal candidates for performing on-chip cryogenic thermometry, in reason of their intrinsically low power dissipation, large temperature sensitivities and excellent sub-μK resolution below 10 K. Through this study, we aim at demonstrating the possibility to enhance the temperature performance of superconducting microwave resonators by means of surface nanostructuring. Different arrays of nanotrenches are strategically patterned on the inductive line of a 1.3 GHz planar resonator, by partially etching a Nb50Ti50 thin-film, in order to tune the critical transition of the material and, therefore, increase the curvature of the fres(T) response. Although the presence of such thinned superconducting regions introduces larger microwave losses, a 1.5 K decrease of TC is recorded, which directly translates into an enhancement of the temperature sensitivity by a factor 10, with respect to a non-nanostructured sensor. A maximum value of dfres/dT = 62 MHz/K, at 4.2 K, is achieved for the device showing the largest nanotrench width of about 350 nm. These results demonstrate that such a surface nanostructuring approach can be exploited as an effective design strategy to tune the fres(T) response of superconducting microwave resonators. Although this technique is found to introduce additional RF losses into the superconducting device, thereby limiting the achievable temperature resolution to the few-μK/Hz1/2 range, we believe that similar approaches could be further investigated for the development of future cryogenic sensors.
Versions
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BibTeX
@misc{chatel2026thinfilm,
title = {{Thin-film nanostructuring of NbTi superconducting resonators for enhanced temperature sensitivity in cryogenic thermometry}},
author = {André Chatel and Roberto Russo and Seyed Alireza Hashemi and Pol Torres-Vila and Jürgen Brugger and Giovanni Boero and Hernán Furci},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2605.01915},
eprint = {2605.01915},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2605.01915},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Thin-film nanostructuring of NbTi superconducting resonators for enhanced temperature sensitivity in cryogenic thermometry
AU - André Chatel
AU - Roberto Russo
AU - Seyed Alireza Hashemi
AU - Pol Torres-Vila
AU - Jürgen Brugger
AU - Giovanni Boero
AU - Hernán Furci
PY - 2026
DA - 2026/10/09
PB - arXiv
DO - 10.48550/arxiv.2605.01915
UR - https://arxiv.org/abs/2605.01915
AB - The rising complexity of cutting-edge cryogenic systems is currently imposing challenging technical constraints to the monitoring of ultra-cold temperatures through standard commercially available sensors. Among different technologies, superconducting microwave resonators have been recently investigated as ideal candidates for performing on-chip cryogenic thermometry, in reason of their intrinsically low power dissipation, large temperature sensitivities and excellent sub-μK resolution below 10 K. Through this study, we aim at demonstrating the possibility to enhance the temperature performance of superconducting microwave resonators by means of surface nanostructuring. Different arrays of nanotrenches are strategically patterned on the inductive line of a 1.3 GHz planar resonator, by partially etching a Nb_50Ti_50 thin-film, in order to tune the critical transition of the material and, therefore, increase the curvature of the f_res(T) response. Although the presence of such thinned superconducting regions introduces larger microwave losses, a 1.5 K decrease of T_C is recorded, which directly translates into an enhancement of the temperature sensitivity by a factor 10, with respect to a non-nanostructured sensor. A maximum value of df_res/dT = 62 MHz/K, at 4.2 K, is achieved for the device showing the largest nanotrench width of about 350 nm. These results demonstrate that such a surface nanostructuring approach can be exploited as an effective design strategy to tune the f_res(T) response of superconducting microwave resonators. Although this technique is found to introduce additional RF losses into the superconducting device, thereby limiting the achievable temperature resolution to the few-μK/Hz^1/2 range, we believe that similar approaches could be further investigated for the development of future cryogenic sensors.
ER -