Nanostructures and nanoelectromechanical devices for precise control of topological defects/matter in superfluid helium

Project Information

N2PCON

Grant agreement ID: 101061892

DOI

10.3030/101061892

Project closed

EC signature date 7 July 2022

Start date 1 August 2022

End date 31 August 2024

Funded under

• Marie Skłodowska-Curie Actions (MSCA)

Total cost

No data

EU contribution

€ 199 694,40

Coordinated by

AALTO KORKEAKOULUSAATIO SR
Finland

Periodic Reporting for period 1 - N2PCON (Nanostructures and nanoelectromechanical devices for precise control of topological defects/matter in superfluid helium)

Reporting period: 2022-08-01 to 2024-08-31

Summary of the context and overall objectives of the project

This project aims developing new nanodevice tools for probing and manipulating phenomena in quantum fluids. To be specific, in the first part of this work, a NEMS-based oscillator has been developed. This nano oscillator should be able to precisely probe quantum vortices in liquid He-3. In the second part of this work, a nanopillar structure has been developed and it should be able to confine quantum vortices and half quantum vortices.

By accomplishing these goals, new tools would be introduced to the research community of quantum fluids, largely accelerating the development of this field. The nanodevices developed in this project could also be exploited in other research communities like medical science, microelectronics, etc.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

1. By introducing a new low-stress SiNx sacrificial layer technology, a sensitive NEMS oscillator was developed. The resonating first-order resonance frequency is below 100 kHz, which fits the measurement scheme. Different designs of oscillators were developed, of which the lightest one is ~2 pg and the highest Q-factor is 8000. These figure-of-merits ensure the capability of precisely probing quantum vortices. Moreover, multiple oscillators on the sample chip were also developed, which allows more possibility of manipulating quantum vortices and probing more fascinating phenomena.

2. By developing a new electron beam lithography patterning technique, I successfully accomplished patterning of an array of circles (11 nm-13 nm) which can be used for the creation of the high-aspect ratio nanostrands. The resulted nanostrands are with 11 nm-13 nm diameter and 200 nm of height, which will satisfy the measurement scheme in liquid He-3.

3. Variation of the nanostrand structures (random structures without an array) were also developed and collaborated with other researchers for more application scenarios. A robust superhydrophobic surface was demonstrated and an optical diffuser application was also demonstrated. The optical diffuser shows light concentration capability which can be used to increase the performance of solar cells.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

In this project, nano-oscillator and nanostrands were developed and key figure-of-merits were analyzed to ensure they can work in He-3. Moreover, regarding the nanostrands, applications towards photonic and superhydrophobic surface were explored with collaborators.

1. In the future, both the oscillator and nanostrands can be deeply integrated with silicon MEMS devices (microgear systems, etc.) to allow more degrees of freedom. In this scenario, more complex measurement in liquid He-3 can be set up.

2. Regarding the oscillator, medical applications like molecular detection can be developed.