Ultralow temperature thermometry with nanoscale devices
Lead Research Organisation:
Lancaster University
Department Name: Physics
Abstract
The goal of cooling materials and structures ever closer to absolute zero temperature has led to significant discoveries in physics and has prompted the development of many new technologies. For example, the phenomena of superfluidity and superconductivity showed that quantum-mechanical effects dominate the behaviour of certain materials at low temperatures. The discovery of the quantum Hall effect has given a new metrological standard for defining voltage, and the discovery of Coulomb blockade may soon allow the ampere to be redefined using devices that generate electrical current one electron at a time. Cooling to very low temperatures can better allow us to observe and control certain materials and structures at a quantum-mechanical level. This continues to drive research in low temperature physics and underpins many efforts to realise new quantum technologies such as quantum computation and advanced sensors.
Present refrigeration technologies allow certain materials to be cooled extremely close to absolute zero. The limit for continuous cooling is around 1 millikelvin, using dilution refrigeration. Additional cooling based on nuclear demagnetisation refrigeration allows some materials can be cooled to less than a hundredth of this temperature. The biggest challenge in using either of these methods to cool an arbitrary sample is making a good thermal connection between the sample and the refrigerator. At low temperatures thermal connections between materials become very small. This can mean, for instance, that the electrons in the metal wires contacting an on-chip device are at a different temperature to that of the chip, and neither are as cold as the refrigerator. This a particular problem in the field of nanoelectronics where the sample has a tiny active volume with a very weak thermal connection to its surroundings. At present, it is extremely challenging to cool nanoelectronic samples significantly below 10 millikelvin.
This project will combine techniques from ultralow temperature physics and nanotechnology to develop new devices that can measure the temperature of electrons in nanoelectronic structures below 1 millikelvin. These thermometers will then be used to build a platform for reaching temperatures of 1 millikelvin or below in arbitrary nanoelectronic samples. Three different thermometers will be studied, before the most promising one is selected for the final stage of the project. All of the thermometers will be essential diagnostic tools throughout the project, informing the development of electrical filters, thermal shielding and refrigeration methods.
The new thermometry techniques will give us a better understanding of nanoscale structures in a currently inaccessible temperature range. This is likely to be a significant benefit to many active areas of research in low temperature physics, quantum computing, nanoscience and metrology.
Present refrigeration technologies allow certain materials to be cooled extremely close to absolute zero. The limit for continuous cooling is around 1 millikelvin, using dilution refrigeration. Additional cooling based on nuclear demagnetisation refrigeration allows some materials can be cooled to less than a hundredth of this temperature. The biggest challenge in using either of these methods to cool an arbitrary sample is making a good thermal connection between the sample and the refrigerator. At low temperatures thermal connections between materials become very small. This can mean, for instance, that the electrons in the metal wires contacting an on-chip device are at a different temperature to that of the chip, and neither are as cold as the refrigerator. This a particular problem in the field of nanoelectronics where the sample has a tiny active volume with a very weak thermal connection to its surroundings. At present, it is extremely challenging to cool nanoelectronic samples significantly below 10 millikelvin.
This project will combine techniques from ultralow temperature physics and nanotechnology to develop new devices that can measure the temperature of electrons in nanoelectronic structures below 1 millikelvin. These thermometers will then be used to build a platform for reaching temperatures of 1 millikelvin or below in arbitrary nanoelectronic samples. Three different thermometers will be studied, before the most promising one is selected for the final stage of the project. All of the thermometers will be essential diagnostic tools throughout the project, informing the development of electrical filters, thermal shielding and refrigeration methods.
The new thermometry techniques will give us a better understanding of nanoscale structures in a currently inaccessible temperature range. This is likely to be a significant benefit to many active areas of research in low temperature physics, quantum computing, nanoscience and metrology.
Planned Impact
The main impact of this project will be new instrumentation and methodology to enable the study of nanoelectronic structures at currently inaccessible temperatures below 1 millikelvin. In addition to advancing the fundamental understanding of heat flow in nanoscale structures, this project aims to improve key enabling technologies - thermometry and refrigeration - that have broad utility in low temperature science and the growing area of Quantum Technologies. Quantum Technologies are anticipated to improve the performance of a variety of sensors with benefits ranging from improved medical imaging to resource exploration. Many proposed quantum technologies, such as enhanced magnetic field sensors and bolometers based on superconducting materials, will need to be operated at sub-kelvin temperatures or even colder. This project is therefore closely aligned with the EPSRC Grand Challenge "Quantum Physics for New Quantum Technologies" and recent UK government investment in Quantum Technologies. The current push to develop practical Quantum Technologies in a short timescale (five years) makes the work proposed in this project especially timely. As well helping to realise the benefits of Quantum Technologies, the importance of improved sensing, metrology, and quantum technologies will be communicated to the general public through publication and outreach activities.
During this project graduate students will be trained in highly desirable skills such as nanofabrication and cryogenic techniques, including skills that are valuable in other sectors such as electronics, low noise measurements, data analysis and scientific computing.
The UK already has a strong commercial presence in low temperature technologies, particularly in the construction of dilution refrigerators. New techniques and knowledge arising from this project are expected have benefits for this market and these will be explored through existing industrial collaborations within and outside the UK. As well as helping to maintain the UK's position in supplying millikelvin refrigerators, these collaborations can explore a potential new market in sub-millikelvin refrigeration for nanoscale samples and devices.
During this project graduate students will be trained in highly desirable skills such as nanofabrication and cryogenic techniques, including skills that are valuable in other sectors such as electronics, low noise measurements, data analysis and scientific computing.
The UK already has a strong commercial presence in low temperature technologies, particularly in the construction of dilution refrigerators. New techniques and knowledge arising from this project are expected have benefits for this market and these will be explored through existing industrial collaborations within and outside the UK. As well as helping to maintain the UK's position in supplying millikelvin refrigerators, these collaborations can explore a potential new market in sub-millikelvin refrigeration for nanoscale samples and devices.
Organisations
- Lancaster University (Lead Research Organisation)
- University of Cambridge (Collaboration, Project Partner)
- University of Manchester (Collaboration, Project Partner)
- CEA-Leti (Collaboration)
- University of Wisconsin-Madison (Collaboration)
- VTT Technical Research Centre of Finland Ltd (Collaboration)
- VTT Technical Research Centre of Finland (Project Partner)
- University of Wisconsin–Madison (Project Partner)
People |
ORCID iD |
Jonathan Prance (Principal Investigator) |
Publications
Autti S
(2023)
Thermal Transport in Nanoelectronic Devices Cooled by On-Chip Magnetic Refrigeration.
in Physical review letters
Bradley D
(2016)
On-chip magnetic cooling of a nanoelectronic device
Bradley DI
(2017)
On-chip magnetic cooling of a nanoelectronic device.
in Scientific reports
Chawner J
(2020)
Non-galvanic calibration and operation of a quantum dot thermometer
Chawner J
(2021)
Nongalvanic Calibration and Operation of a Quantum Dot Thermometer
in Physical Review Applied
Haley R
(2021)
Breaking the millikelvin barrier in nanoelectronics
in Europhysics News
Jones AT
(2020)
Progress in Cooling Nanoelectronic Devices to Ultra-Low Temperatures.
in Journal of low temperature physics
Samani M
(2022)
Microkelvin electronics on a pulse-tube cryostat with a gate Coulomb-blockade thermometer
in Physical Review Research
Description | We found that a particular type of electronic thermometer (a Coulomb Blockade Thermometer) is able to measure the temperature of electrons in a nanoelectronic structure down to ~1 millikelvin. Furthermore, our results suggest that this type of thermometer should be able to function at sub-millikelvin temperatures with relatively straightforward modifications. In order to reach these findings, we also developed a new refrigeration technique - on-chip demagnetisation refrigeration - which was then integrated into our thermometer device. It has recently been demonstrated that this technique can be extended into the sub-millikelvin regime (arXiv:1903.01388). We have also developed a thermometry technique that is able to measure the temperature of an on-chip electron bath without requiring a direct (DC) electrical connection to the outside world. The thermometer is a quantum dot measured by RF reflectometry (arXiv:2012.01209). |
Exploitation Route | Commercial manufacturers of ultralow-temperature instruments (in the UK and abroad) could now consider incorporating Coulomb Blockade Thermometers in their products, since they are now known to operate down to the lowest temperatures offered to customers. We have been actively promoting the technology to our industrial contacts and collaborators and believe there is now increased interest in this technology. The on-chip refrigeration technique has also been adopted by other groups (doi:10.1103/PhysRevApplied.12.011005, doi:10.1063/1.5002565). As the technique is used more widely, it may lead to academic impact by opening a new temperature range for the study of electronic materials and nanostructures. |
Sectors | Digital/Communication/Information Technologies (including Software),Electronics,Other |
Description | Our work on CBT thermometers has helped to renew commercial interest in their production. One of our collaborators, VTT (Finland), is continuing to investigate new ways to produce CBTs that will make them more commercially attractive and easier to use in practice. |
Sector | Electronics |
Impact Types | Economic |
Title | CBT demagnetisation data |
Description | Experimental data from measurements of on-chip cooling of a Coulomb Blockade Thermometer, including metadata and documentation. The dataset was published online in October 2016. |
Type Of Material | Database/Collection of data |
Provided To Others? | No |
Impact | N/A |
Title | Measurements of a quantum dot thermometer using RF reflectometry |
Description | Data from the calibration and operation of a silicon quantum dot thermometer at temperatures between 10mK and 3K. The device is a silicon-on-insulator trigate accumulation-mode field-effect transistor from CEA/LETI-MINATEC, Grenoble, France. The device is measured using RF reflectometry to observe changes in its gate capacitance.Description |
Type Of Material | Database/Collection of data |
Year Produced | 2020 |
Provided To Others? | Yes |
Impact | Development of a technique to measure electron temperature without any direct (galvanic) electrical connection to external circuits. |
URL | http://www.research.lancs.ac.uk/portal/en/datasets/measurements-of-a-quantum-dot-thermometer-using-r... |
Description | CBT development (Lancaster & VTT) |
Organisation | VTT Technical Research Centre of Finland Ltd |
Country | Finland |
Sector | Academic/University |
PI Contribution | Testing of new prototype CBTs (Coulomb Blockade Thermometers) at low-millikelvin temperatures. Measurement of on-chip demagnetisation refrigeration of a CBT. |
Collaborator Contribution | VTT have supplied us with several CBTs for testing. The devices have a range of charging energies and some are plated with copper for on-chip refrigeration. |
Impact | Collaboration is not multi-disciplinary. No published outputs to-date (one in preparation). |
Start Year | 2016 |
Description | Quantum dot thermometry |
Organisation | CEA-Leti |
Country | France |
Sector | Charity/Non Profit |
PI Contribution | We measure quantum dot devices at low temperatures to assess their potential as thermometers of electron temperature in nanoscale devices. |
Collaborator Contribution | CEA-Leti and Hitachi Cambridge Laboratory produce silicon FinFET devices. Hitachi Cambridge Laboratory provides expertise in high-frequency measurement of the devices. |
Impact | "Non-galvanic calibration and operation of a quantum dot thermometer", https://arxiv.org/abs/2012.01209 |
Start Year | 2017 |
Description | Quantum dot thermometry |
Organisation | Hitachi Cambridge Laboratory |
Country | United Kingdom |
Sector | Private |
PI Contribution | We measure quantum dot devices at low temperatures to assess their potential as thermometers of electron temperature in nanoscale devices. |
Collaborator Contribution | CEA-Leti and Hitachi Cambridge Laboratory produce silicon FinFET devices. Hitachi Cambridge Laboratory provides expertise in high-frequency measurement of the devices. |
Impact | "Non-galvanic calibration and operation of a quantum dot thermometer", https://arxiv.org/abs/2012.01209 |
Start Year | 2017 |
Description | Superconducting graphene thermometry (Lancaster & Manchester) |
Organisation | University of Manchester |
Department | School of Physics and Astronomy Manchester |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | We have conducted low temperature (millikelvin) characterisation of graphene devices fabricated at Manchester. |
Collaborator Contribution | Manchester has provided (and continues to provide) graphene devices that are being tested as thermometers and bolometers at Lancaster. |
Impact | The collaboration is not multi-disciplinary. No outputs to-date. |
Start Year | 2016 |
Description | Thermometry for silicon QIP (Lancaster & UW-Madison) |
Organisation | University of Wisconsin-Madison |
Department | Department of Physics |
Country | United States |
Sector | Academic/University |
PI Contribution | I visited the lab of Mark Eriksson (UW-Madison) in the summer of 2016 to characterise the electron temperature in their qubit measurement platform. Using the results, we were able to improve the qubit environment by lowering electrical noise. |
Collaborator Contribution | UW-Madison provided access to a dilution refrigerator and SiGe samples for 3 weeks to conduct measurements. Their expertise in qubit measurements will continue to guide our development of thermometers so that they can be useful to the solid-state QIP community. UW-Madison paid for travel and accommodation during lab visit. |
Impact | No outputs to-date. This collaboration is not multi-disciplinary. |
Start Year | 2016 |
Description | New Scientist Live |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Public/other audiences |
Results and Impact | A team of 13 academics, postdoctoral researchers and postgraduate students from Lancaster University created a stand to exhibit at New Scientist Live in London (ExCeL centre, 20-23 Sept, 2018). The stand sought to engage the general public to explain and disseminate research taking place in the IsoLab facility at Lancaster. Part of the stand was focused on low temperature physics and experimental techniques of isolation for low temperature experiments. In total, nearly 40,000 people attended New Scientist live and a further 400,000 engaged online. This included our own promotional videos, which were viewed ~60,000 times in total. In addition to dissemination of results, the activity resulted in new industry contacts and a plan to expand the exhibit for the Royal Society Summer Science Exhibition in 2019. |
Year(s) Of Engagement Activity | 2018 |
URL | https://live.newscientist.com/exhibitors/lancaster-university |
Description | Physics Headstart course at Lancaster University |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | No |
Geographic Reach | National |
Primary Audience | Schools |
Results and Impact | 40 pupils attend a week-long residential course at Lancaster University. They undertook different activities on each day, with one workshop on quantum computing and related technologies, including cryogenics. This part of the course was run by myself and a second academic. As in previous years, the intended purpose is to give the pupils some experience of University life and study, to help them back better choices about their future. |
Year(s) Of Engagement Activity | 2018 |
Description | Physics Headstart course at Lancaster University |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | No |
Geographic Reach | National |
Primary Audience | Schools |
Results and Impact | 30 pupils attended a one-week residential course at Lancaster Physics organised with Headstart. I ran a workshop on quantum computing and gave a related talk on low temperature quantum technologies. After the end of the course, 96% of students said that they enjoyed the QT activity and 86% of attendees said that they felt better informed about their future study choices. |
Year(s) Of Engagement Activity | 2017 |
Description | WOMAD festival Physics Pavilion |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | National |
Primary Audience | Public/other audiences |
Results and Impact | The Physics Pavilion at the WOMAD (world music and dance) festival presented talks, live demos and activities spanning a range of physics topics. I contributed by giving a talk (typical audience ~50) and demonstrations of low temperature physics (typical audience ~50). |
Year(s) Of Engagement Activity | 2017 |
URL | http://womad.co.uk/inspire-discover-explore-physics-pavilion-womad-2017/ |