A Diamond Bridge to Phase Slip Physics
Lead Research Organisation:
CARDIFF UNIVERSITY
Department Name: School of Physics and Astronomy
Abstract
Metrology - the science of measurement - underpins almost everything we encounter on a daily basis. An everyday example of metrology is when very small weights of medicine are weighed out to give precise doses. In this instance, without a clear and common understanding of the unit of mass, there could easily be dire consequences for the patient. The unit of mass - the kilogram - was historically defined by a physical object made of platinum and housed in a vault in the outskirts of Paris, with several copies held around the world. These copies were unavoidably imperfect, in that one could never have the exact same number of platinum atoms in each copy, and hence small errors in the definition of the kilogram were inevitable.
Since 2019, however, the kilogram has been redefined in terms of the fundamental constants of nature and, somewhat counterintuitively, measured electronically. This therefore requires a common agreement in the units of electrical measurement - the volt (voltage), the Ohm (resistance), and the Ampere (current) - as is familiar from any light bulb packaging. Of these three electrical units, we have a very precise agreement on the magnitude of a volt and an Ohm, both of which are defined by the results of quantum mechanical experiments and are precise to a very high degree. The Ampere, however, still lacks a quantum mechanical definition of its own and is defined in terms of other units.
There are numerous proposals for systems that exploit quantum mechanics to provide an independent and precise definition of the Ampere. One such proposal uses superconductors - materials that lose all electrical resistance at very low temperatures and are large scale quantum mechanical objects in of themselves. Using superconductors to make a quantum current standard, however, has so far been difficult because it has been thought necessary to make very small structures - many hundreds of times narrower than a typical human hair - to induce the necessary behaviour to define the Ampere. The research proposed here will work towards a quantum mechanical definition of the Ampere that uses an alternative material - superconducting diamond - in place of more traditional superconducting materials.
In previous work, we have found that the internal structure of thin diamond films allows us to reproduce the prerequisite behaviours necessary for the definition of the Ampere, but at a comparatively large physical scale - only tens of times narrower than a human hair! Though this still seems small, making and measuring objects of this size is vastly more simple than previous approaches. We will make electrical circuits out of thin superconducting diamond films that are designed to help us quantum mechanically define the magnitude of the Ampere.
The unique internal structure of superconducting diamond results in a host of other promising applications in quantum technologies that will also be explored during the course of this research.
Since 2019, however, the kilogram has been redefined in terms of the fundamental constants of nature and, somewhat counterintuitively, measured electronically. This therefore requires a common agreement in the units of electrical measurement - the volt (voltage), the Ohm (resistance), and the Ampere (current) - as is familiar from any light bulb packaging. Of these three electrical units, we have a very precise agreement on the magnitude of a volt and an Ohm, both of which are defined by the results of quantum mechanical experiments and are precise to a very high degree. The Ampere, however, still lacks a quantum mechanical definition of its own and is defined in terms of other units.
There are numerous proposals for systems that exploit quantum mechanics to provide an independent and precise definition of the Ampere. One such proposal uses superconductors - materials that lose all electrical resistance at very low temperatures and are large scale quantum mechanical objects in of themselves. Using superconductors to make a quantum current standard, however, has so far been difficult because it has been thought necessary to make very small structures - many hundreds of times narrower than a typical human hair - to induce the necessary behaviour to define the Ampere. The research proposed here will work towards a quantum mechanical definition of the Ampere that uses an alternative material - superconducting diamond - in place of more traditional superconducting materials.
In previous work, we have found that the internal structure of thin diamond films allows us to reproduce the prerequisite behaviours necessary for the definition of the Ampere, but at a comparatively large physical scale - only tens of times narrower than a human hair! Though this still seems small, making and measuring objects of this size is vastly more simple than previous approaches. We will make electrical circuits out of thin superconducting diamond films that are designed to help us quantum mechanically define the magnitude of the Ampere.
The unique internal structure of superconducting diamond results in a host of other promising applications in quantum technologies that will also be explored during the course of this research.
People |
ORCID iD |
Georgina Klemencic (Principal Investigator) |
Publications
Bose M
(2022)
Low-Noise Diamond-Based D.C. Nano-SQUIDs
in ACS Applied Electronic Materials
Cuenca J
(2023)
Superconducting boron doped nanocrystalline diamond microwave coplanar resonator
in Carbon
Klemencic G
(2021)
Phase slips and metastability in granular boron-doped nanocrystalline diamond microbridges
in Carbon
Manifold S
(2021)
Contact resistance of various metallisation schemes to superconducting boron doped diamond between 1.9 and 300 K
in Carbon
Perkins D
(2021)
Fluctuation spectroscopy in granular superconductors with application to boron-doped nanocrystalline diamond
in Physical Review B
Description | So far, three main findings can be briefly summarised: 1. We have demonstrated a method by which individual phase slip formation in granular diamond microbridges can be induced and undone by a controlled external source - thereby demonstrating a prototype superconducting memory device with write-read-reset functionality that can be made using a single-step fabrication method (paper forthcoming). 2. In collaboration with theorist colleagues at the Universities of Bristol and Birmingham, we have made advances in the theory of granular superconductivity that will aid in the analysis of the data produced by this project. This is a detailed analysis of the temperature dependence of the resistance in granular superconductors, which focuses on the grain size regime that our granular diamond samples fit into (paper published). 3. We have recently shown that the granularity and disorder in these diamond films do not preclude their use in low-temperature microwave circuitry. We extract key material parameters that have not yet been measured directly for granular diamond films. Notably, we extract the magnetic penetration depth, which is a crucial value needed for the design of future superconducting devices made from this material and for the understanding of the underlying phase slip formation that is focused on in this work (paper forthcoming). This is an ongoing grant - further findings to follow. |
Exploitation Route | With reference to the outcomes listed above: 1. The ability to induce and undo phase slip formation has - to date - only been demonstrated in strictly one-dimensional superconducting structures. Here, we use the underlying film structure to enable this. The mechanism behind the read-write-reset functionality demonstrated can indicate future pathways for the development of future superconducting memory devices. 2. This detailed analysis is applicable to a large family of superconducting materials that are gaining popularity for device fabrication as quantum technologies mature and may find use in material characterisation for device applications. 3. This is a result of interest of anyone thinking of making a microwave device out of this material - or materials with a similar level of granularity/disorder. This has not yet been demonstrated by other groups and so indicates that an entirely single-step lithography device that uses microwave signals is possible with this material. The extracted values will be of direct use for the analysis and understanding of the results of this work. |
Sectors | Digital/Communication/Information Technologies (including Software),Electronics,Other |
Description | Advanced Spectroscopic Techniques for Separating Natural and Synthetic Diamond Gemstones |
Amount | £90,000 (GBP) |
Funding ID | 2727968 |
Organisation | Engineering and Physical Sciences Research Council (EPSRC) |
Sector | Public |
Country | United Kingdom |
Start | 09/2022 |
End | 09/2026 |
Description | EPSRC Equipment Call 2022 - Cardiff University |
Amount | £757,080 (GBP) |
Funding ID | EP/X034739/1 |
Organisation | Engineering and Physical Sciences Research Council (EPSRC) |
Sector | Public |
Country | United Kingdom |
Start | 01/2023 |
End | 07/2024 |
Description | Superconducting Diamond for a Quantum Current Standard |
Amount | £80,000 (GBP) |
Funding ID | 2727968 |
Organisation | Engineering and Physical Sciences Research Council (EPSRC) |
Sector | Public |
Country | United Kingdom |
Start | 09/2022 |
End | 03/2026 |
Title | Experimental dataset for: Superconducting boron doped nanocrystalline diamond microwave coplanar resonator |
Description | This dataset contains experimental measurements of the boron doped nano-crystalline diamond (B-NCD) microwave coplanar resonator (CPR). Within this dataset, the following information is provided: - Raman spectroscopy - Finite Element Modelling results - Microwave wideband CPR data (At temperatures of 100 mK and 3,000 mK) - Microwave fine CPR data of the first 3 modes (At temperatures from 100 mK to 1,750 mK) |
Type Of Material | Database/Collection of data |
Year Produced | 2022 |
Provided To Others? | Yes |
Impact | Data is available for the analysis of highly granular superconducting resonators. The magnetic field penetration was found to be several orders of magnitude larger than reported in the literature. Too early to attribute further impact. |
URL | https://research.cardiff.ac.uk/converis/portal/detail/Dataset/218422459?auxfun=&lang=en_GB |
Description | Cardiff/La Trobe/Melbourne |
Organisation | La Trobe University |
Country | Australia |
Sector | Academic/University |
PI Contribution | Discussion of data, provision of materials, remote supervision, expertise and intellectual input |
Collaborator Contribution | Sample measurement, data analysis, expertise and intellectual input |
Impact | One paper published so far |
Start Year | 2021 |
Description | Cardiff/La Trobe/Melbourne |
Organisation | University of Melbourne |
Country | Australia |
Sector | Academic/University |
PI Contribution | Discussion of data, provision of materials, remote supervision, expertise and intellectual input |
Collaborator Contribution | Sample measurement, data analysis, expertise and intellectual input |
Impact | One paper published so far |
Start Year | 2021 |
Description | Expert panel participation (recurring) |
Form Of Engagement Activity | A formal working group, expert panel or dialogue |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Professional Practitioners |
Results and Impact | Provided expertise for a funding review panel (low-temperature technologies). Influenced funding decisions made. |
Year(s) Of Engagement Activity | 2021,2023 |
Description | Open days (recurring) |
Form Of Engagement Activity | Participation in an open day or visit at my research institution |
Part Of Official Scheme? | No |
Geographic Reach | National |
Primary Audience | Public/other audiences |
Results and Impact | Presentations and lab visits from applicants and the general public spanning many years. Visitors hear about the research being conducted in Cardiff, including that supported by this grant. Many of these visits are converted to applications made to the university to study physics. |
Year(s) Of Engagement Activity | 2021,2022,2023 |
Description | Participation (IOP Quantum Technology for Fundamental Physics workshop) |
Form Of Engagement Activity | A formal working group, expert panel or dialogue |
Part Of Official Scheme? | No |
Geographic Reach | National |
Primary Audience | Professional Practitioners |
Results and Impact | Workshop organised by the Institute of Physics' Low Temperature committee focusing on Quantum Technology for Fundamental Physics. Presentations were organised followed by discussion and networking. |
Year(s) Of Engagement Activity | 2022 |
Description | Participation (Materials for Quantum Network launch event) |
Form Of Engagement Activity | A formal working group, expert panel or dialogue |
Part Of Official Scheme? | No |
Geographic Reach | National |
Primary Audience | Professional Practitioners |
Results and Impact | Attended the launch event for the Materials for Quantum Network and engaged with focus group discussions on superconductivity and early career researchers. Networking, presentations, and focus groups are encouraging cross-discipline collaboration across academia and industry. |
Year(s) Of Engagement Activity | 2023 |
Description | Poster presentation (15th European Conference on Applied Superconductivity 2021) |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Professional Practitioners |
Results and Impact | Online poster presentation to a wide international low-temperature audience to present new results. New contacts were made and results disseminated. |
Year(s) Of Engagement Activity | 2021 |
URL | https://ieeecsc.org/event/eucas-2021 |
Description | Presentation (2022 MRS Spring Meeting & Exhibit) |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Professional Practitioners |
Results and Impact | Presentation to audience of specialists in superconductivity focus session at an international conference, which sparked questions and discussion and led to a more detailed discussion with a number of researchers afterwards. New contacts were made following these discussions. |
Year(s) Of Engagement Activity | 2022 |
Description | Presentation (Elsevier 31st International Conference on Diamond and Carbon Materials) |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Professional Practitioners |
Results and Impact | Online presentation to the international diamond materials community presenting early experimental results and interpretation. Introduced new applications to the wider community. |
Year(s) Of Engagement Activity | 2021 |
Description | Presentation (German Physical Society/DPG 2022) |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Professional Practitioners |
Results and Impact | Presentation to an international focus session (Disordered and granular superconductors: fundamentals and applications in quantum technology). Questions/discussions followed and new contacts were made following these discussions. |
Year(s) Of Engagement Activity | 2021 |
Description | Presentation (Hasselt Diamond Workshop) |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Professional Practitioners |
Results and Impact | 187 participants attended the international workshop that focused on diamond-related research and technologies. The presentation focused on the influence of doping on diamond conductivity and I showed new results to the community. The presentation sparked a number of questions/discussions and has resulted in at least two new potential collaborations. |
Year(s) Of Engagement Activity | 2022 |
URL | https://www.uhasselt.be/sbdd |
Description | Presentation (IOP LT workshop) |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Professional Practitioners |
Results and Impact | Presentation during IOP's low temperature workshop on New Physics at Low Temperatures, with national and international attendance. Questions/discussion sparked, increased interest in subject discussed. |
Year(s) Of Engagement Activity | 2021 |
Description | Presentation (IOP Xmas lecture) |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | Regional |
Primary Audience | Schools |
Results and Impact | 150 students attended for a school visit to the School of Physics for Xmas lectures organised by the Institute of Physics. My presentation focused on low temperature physics, including demos, where students were encouraged to ask questions and participate. Schools reported a high level of engagement from their students and increased interest in the subject area. |
Year(s) Of Engagement Activity | 2022 |
Description | Presentation (International Women's Day - TWiSTEM) |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | Local |
Primary Audience | Postgraduate students |
Results and Impact | Online International Women's Day talk aimed at undergraduate/postgraduate students in the Trevithick Women in STEM (TWiSTEM) group at Cardiff University. Aimed to discuss career progression for those interested in ED&I matters. The audience reported feeling inspired/encouraged. |
Year(s) Of Engagement Activity | 2021 |