Contributors: Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 (IEMN); Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF); Nano and Microsystems - IEMN (NAM6 - IEMN); Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)-Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF); Ultra-basses températures (NEEL - UBT); Institut Néel (NEEL); Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes 2016-2019 (UGA 2016-2019 )-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes 2016-2019 (UGA 2016-2019 ); Nanofabrication (NEEL - Nanofab); Thermodynamique et biophysique des petits systèmes (NEEL - TPS); A C K N O W L E D G M E N T S :We acknowledge the use of the Néel facility Nanofab for the device fabrication, and the Néel Cryogenics facility with especially Anne Gerardin for realization of mechanical elements of the demagnetization cryostat. X.Z. and E.C. thank Olivier Arcizet and Benjamin Pigeau for help in room-temperature characterization of the NEMS devices using optics; E.C. also thanks O. Arcizet, M. Sillanpää,K. Lehnert, J. Teufel, S. Barzanjeh, K. Schwab, J. Parpia, and M. Dykman for very useful discussions. We acknowledge support from the ERC CoG Grant ULT-NEMS No. 647917, StG Grant UNIGLASS No. 714692, and theSTaRS-MOC project from Région Hauts-de-France. The research leading to these results has received funding fromthe European Union’s Horizon 2020 Research and Innovation Programme, under Grant Agreement No. 824109, theEuropean Microkelvin Platform (EMP). Note added.—Recently, a collaboration between Aalto University and Institut Néel has started with the aim of cooling down a drumhead Al device as low as possible on our adiabatic nuclear demagnetization platform. We have evidence that the same features as for beams are present, at a different level of expression. This shall be publishedelsewhere.; European Project: 647917,H2020,ERC-2014-CoG,ULT-NEMS(2015); European Project: 714692,H2020,ERC-2016-STG,UNIGLASS(2017); European Project: 824109,H2020,H2020-INFRAIA-2018-1,EMP(2019)
نبذة مختصرة : International audience ; We report on microwave optomechanics measurements performed on a nuclear adiabatic demag-netization cryostat, whose temperature is determined by accurate thermometry from below 500 µK to about 1 Kelvin. We describe a method for accessing the on-chip temperature, building on the blue-detuned parametric instability and a standard microwave setup. The capabilities and sensitivity of both the experimental arrangement and the developed technique are demonstrated with a very weakly coupled silicon-nitride doubly-clamped beam mode of about 4 MHz and a niobium on-chip cavity resonating around 6 GHz. We report on an unstable intrinsic driving force in the coupled microwave-mechanical system acting on the mechanics that appears below typically 100 mK. The origin of this phenomenon remains unknown, and deserves theoretical input. It prevents us from performing reliable experiments below typically 10-30 mK; however no evidence of thermal decou-pling is observed, and we propose that the same features should be present in all devices sharing the microwave technology, at different levels of strengths. We further demonstrate empirically how most of the unstable feature can be annihilated, and speculate how the mechanism could be linked to atomic-scale two level systems. The described microwave/microkelvin facility is part of the EMP platform, and shall be used for further experiments within and below the millikelvin range.
Processing Request
No Comments.