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Soft-Clamped Silicon Nitride String Resonators at Millikelvin Temperatures
Thomas Gisler1, Mohamed Helal1, Deividas Sabonis1
1Laboratory for Solid State Physics, ETH Zürich, 8093 Zürich, Switzerland.
Physical Review Letters
|September 16, 2022
Summary
Soft-clamped silicon nitride strings achieve ultra-high quality factors (Q) above 10^9 at millikelvin temperatures. This demonstrates excellent thermalization and potential for sensitive nanomechanical force sensing applications.
Area of Science:
- Physics
- Materials Science
- Nanotechnology
Background:
- Silicon nitride strings are promising for nanomechanical systems.
- Operating devices at millikelvin temperatures is crucial for reducing thermal noise.
Purpose of the Study:
- To investigate the performance of soft-clamped silicon nitride strings at millikelvin temperatures.
- To determine the quality factors and thermal properties of these devices.
Main Methods:
- Fabrication of soft-clamped silicon nitride strings with high aspect ratio.
- Operation and measurement of mechanical modes at mK temperatures using optical readout.
- Analysis of quality factor (Q) dependence on cryostat temperature and readout power.
Main Results:
- Soft-clamped silicon nitride strings operated successfully at mK temperatures.
- Achieved quality factors (Q) exceeding 10^9 at ~46 mK.
- Observed Q saturation at low optical readout power, indicating good thermalization.
- Calculated force sensitivity of 9.6 zN/sqrt[Hz] and thermal decoherence time of 0.38 s.
Conclusions:
- Soft-clamped silicon nitride strings exhibit excellent mechanical properties at mK temperatures.
- The devices demonstrate high thermalization, crucial for sensitive measurements.
- These results support the use of such strings in advanced nanomechanical force sensing applications.
