Quantum Effects in Electronic Nanodevices (QuEEN)

Lead Research Organisation: University of Oxford
Department Name: Materials

Abstract

Put your hand under a working laptop computer and you'll find that it's warm, due to the heat produced by the transistors in it. This isn't just a problem for your own computer: nearly 5% of the world's electricity is used by computers and the internet, a figure expected to double over the next decade. Much of this is wasted in generating heat that, according to thermodynamic theory, is not needed for information processing; and over half is for cooling systems to remove the unwanted heat. The resulting carbon emissions are comparable to the total global aviation industry.

If we can reduce the energy consumption of logic operations in information technologies, or scavenge just a fraction of the waste heat, the effect on energy use and carbon emissions could be vast. Recent research breakthroughs have opened up new possibilities for making tiny electronic components and circuits, based on individual molecules, which have the potential to do just that (since their behaviour is not constrained by the laws of classical physics). To make this a reality, we must first learn to understand and control quantum effects in electronic nanodevices.

We can use a new material, graphene, to make mechanically and chemically stable electrodes and connect them to electrically-active molecules. New methods allow us to make a very small gap in graphene which is just the right size for a molecule or a single strand of DNA (for fast and cheap DNA sequencing). Chemical units have been developed that attach to molecules and adhere like sticky notes to the graphene contacts on each side of the gap.. With graphene electrodes we can also make magnetic connections to single molecules to create molecular memory devices. A phenomenon called quantum interference can dramatically affect the flow of electric current in molecules. Harnessing these quantum effects will enable us to make tiny switches that would consume very little energy, and to generate electricity from small differences in temperature. The time is ripe for a focused research effort, drawing together these advances to transform our understanding and to pave the way for practical applications.

Our programme is one of discovery science with a view to practical benefit. QuEEN will first establish the basic platform technology for experiments on single-molecule devices, including selection of the best molecules and control of their quantum interference by a local electric field. It will conclude by seeking to transfer results from rather ideal (cryogenic) laboratory conditions to a real-world environment, at room temperature. In between those two challenges, we shall explore three particularly promising areas for scientific discovery and application: controlling the magnetic property of an electron, known as spin, for quantum interference for potential use in universal computer memories; seeing how much electricity a molecule can generate if its ends are held at different temperatures, offering the potential for energy harvesting; and finding the performance limits of a single-molecule transistor, for potential uses in low-power computing and timer-controllers for the Internet of Things.

The research requires four core skill sets, which form a virtuous circle: chemistry, to design and synthesise the molecules at the heart of our devices and stick them reliably to electrodes; nanofabrication, to make molecule-sized gaps in graphene ribbons; measurement techniques and advanced instrumentation to control the environment and characterise the quantum effects; and theory, to predict the effects, screen potential molecules, and interpret the results. QuEEN brings together a research team with exactly the right mix of expertise; an Advisory Board with wide experience of successful technological entrepreneurship; and a group of industrial partners who will not only shape and assist with the research but also provide a pathway to technological innovation and real-world applications.

Planned Impact

If we can (a) harness quantum interference, and other effects, in graphene-based single-molecule devices; and (b) demonstrate the practical and commercial viability of such devices (in terms of performance and reproducibility) compared to existing technologies, then that could pave the way for major long-term economic and societal benefits.

Ultimately, ultra-low power transistors and/or thermo-electric energy recovery methods (enabling the design of high-performance thin-film materials which convert waste heat to electricity) could significantly reduce electricity consumption in ICT. This would not only reduce running costs for end users around the world, and for customers of data-intensive services, but also contribute to the wider goal of low-carbon economies. Reduced power consumption in sensors, which has the effect of extending usable battery lifetimes, will also be an important enabler for the Internet of Things.

Our work on harnessing magnetic properties could lay the foundations for new 'universal' computer memory technologies, which would further reduce power consumption and increase speed and efficiency (by removing the existing requirement for separate memories for computation and for storage).

These disruptive technologies would open up major new commercial opportunities for electronics and ICT component manufacturers, including next-generation products to replace current technologies, alongside entirely new markets and products. They would stimulate job creation and the establishment of new companies, and promote inward R&D investment into the UK by major multi-national companies.

These are all long-term outcomes that will require further translational research by physicists, engineers and computer scientists to build on our results - addressing issues such as manufacturability, scale-up, and integration - and take our devices from laboratory proof-of-concept to real-world application.

In the nearer term, the QuEEN programme will deliver economic and commercial benefits in at least two ways:

- our patented graphene nanogaps show significant promise as a route to enhanced DNA sequencing technologies; collaborative work with a commercial project partner will seek to exploit this;

- the sensitive, low-noise electronic measurement systems we will develop will be of interest to cryogenic instrument manufacturers, and could lead to new or improved products.

Throughout the programme, we shall work with our experienced Advisory Board, our Project Partners and the UK National Quantum Technologies Hub network to identify other (niche) opportunities for near-term application and impact.
 
Title How does electricity flow through small objects? (Oxford Sparks animation) 
Description How does electricity flow through small objects? An animation by Oxford Sparks for a wide audience, including schoolchildren. 
Type Of Art Film/Video/Animation 
Year Produced 2018 
Impact Over 3,000 views to date. 
URL https://www.oxfordsparks.ox.ac.uk/content/how-does-electricity-flow-through-small-objects
 
Description Thermopower of a single molecule
Exploitation Route Low power consumption ICT
Sectors Creative Economy,Digital/Communication/Information Technologies (including Software),Electronics

URL https://queenprogramme.org
 
Description Molecular sensing 
Organisation Oxford Nanopore Technologies
Country United Kingdom 
Sector Private 
PI Contribution Patented method for forming graphene nanogaps
Collaborator Contribution Genome sequencing
Impact Publications and technology
Start Year 2016
 
Description How does electricity flow through small objects? (Oxford Sparks animation) 
Form Of Engagement Activity A broadcast e.g. TV/radio/film/podcast (other than news/press)
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact How does electricity flow through small objects? An animation by Oxford Sparks for a wide audience, including schoolchildren.
Year(s) Of Engagement Activity 2018
URL https://www.oxfordsparks.ox.ac.uk/content/how-does-electricity-flow-through-small-objects
 
Description The Curious Science Quest (OUMNH) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Schools
Results and Impact The Curious Science Quest: presentation by Julia Golding of her series for children based on The Penultimate Curiosity by Roger Wagner and Andrew Briggs, held at the Oxford University Museum of Natural History.
Year(s) Of Engagement Activity 2018
URL http://goldinggateway.com/julia-golding/curious-science-quest/
 
Description The Curious Science Quest (RI) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Schools
Results and Impact Julia Golding presented The Curious Science Quest to an audience of schoolchildren and general public at the Royal Institution.
Year(s) Of Engagement Activity 2019
URL http://goldinggateway.com/julia-golding/curious-science-quest/
 
Description Wigner Distinguished Lecture (ORNL) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact ORNL's Eugene P. Wigner Distinguished Lecture Series in Science, Technology, and Policy promotes dialogue among Oak Ridge researchers and renowned leaders in science, industry, and government. The invited lecturers bring distinct perspectives to the lab's community of scientists and engineers, whose scientific discoveries and technological breakthroughs target some of the world's most pressing problems.
Year(s) Of Engagement Activity 2016
URL https://www.ornl.gov/content/wigner-distinguished-lecture-series
 
Description Wonder in carbon land: how do you hold a molecule? 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact Carbon is a unique element because bonds are easily made between carbon atoms. This allows carbon to form complex structures such as the 'Buckyball' a tiny cage made up of 60 carbon atoms. Scientists are using these nanocages and other structures known as nanotubes to create unique products and to explore the properties of atoms.

'Once an atom is contained within a nanocage it can't react with anything allowing us to examine the atom's individual properties,' explains Andrei Khlobystov, a chemist at the University of Nottingham. 'Nanotubes are used to contain reactions, just like a regular test tube, but in a much more controlled way.'

When a reaction takes place in a normal test tube the product can be unpredictable as branches can form at random points along the chains of molecules. Within the miniscule confines of a nanotube branching is not possible so the products of reactions are uniform chains of molecules.

'We pump molecules into a nanotube, and use light or heat to set off the reaction,' says Andrei. 'The molecules react to form polymers or plastics whose properties are entirely based on the molecular structure. So by precise control of the molecular structure you can build products with specific properties, such as mechanical strength.'

'Come along to our exhibit and get involved. We'll be building giant fullerene origami models which you can add your own graffiti art to. Leave your signature or a scribble. We're also going to have plenty of hands-on activities, give-aways and demos. There's even going to be a magician performing illusions related to quantum computing. We look forward to seeing you!' say the exhibit team.
Year(s) Of Engagement Activity 2008
URL https://royalsociety.org/science-events-and-lectures/2008/summer-science/carbon-land/