Quantum spintronics using donors in isotopically engineered silicon

Lead Research Organisation: University of Oxford
Department Name: Materials

Abstract

The exquisite control over materials fabrication and spin control techniques has reached a maturity where spintronics can go beyond purely classical effects and begin to fully exploit the unique quantum properties of superposition and entanglement. Potential applications arising from quantum spintronics range from quantum information processors, including the transmission of quantum information via itinerant electron spins, single microwave photon storage within spin ensembles, and new generation of sensors exploiting entanglement to yield fundamentally enhanced precision. Key ingredients for quantum spintronics include the preservation of spin coherence and the generation of high-purity entanglement. Through this collaborative research project, we propose to address both of these challenges using both the electron and nuclear spin of donors in isotopically engineered silicon. Our preliminary experiments show that such materials offer the greatest potential for high-purity entanglement and long coherence times, and their potential integration within conventional electronics is a further advantage.Through our initial collaboration, we have already demonstrated 'psuedo-entanglement' between the electron and nuclear spin associated with a P-donor in silicon at X-band (0.3 T) and 6K. We have used the fidelities which we achieved in those experiments to calculate thresholds for generating pure entanglement by this technique: for example moving to higher magnetic fields (>3.5T) and lower temperatures (<4K). We possess the major instrumentation to meet these requirements, and will demonstrate the controlled generation of pure spin entanglement within silicon as part of this project. We will then develop methods for preserving entanglement and understand the effect of spin transport.The isotopic purification of silicon to 28Si yields dramatic improvements in the donor electron spin coherence to tens of milliseconds. However, the nuclear spin is a powerful resource into which the coherent electron spin state may be temporarily stored and retrieved. We have demonstrated the use of the nuclear spin as a quantum memory in this way, yielding coherence times up to several seconds. We will understand the mechanisms for spin decoherence and, using materials refinement and active techniques such as dynamic decoupling and error-correction, we will push the limits of the longest spin coherences times in the solid state. The spin ensembles which we will be studying are capable of storing multiple bits of information in distributed states, analogous to holographic information storage. We shall build on our initial work, in which we stored and retrieved 100 coherent weak microwave excitations within an ensemble, to establish multimode quantum memories working i) at low applied magnetic fields ii) down to the single photon level iii) capable of storing coherent quantum states for several seconds.Throughout this project we will be performing an iterative development of instrumentation and materials: longer coherence times enabled by the isotopically engineered materials will push us to the limits of our instrumentation, and by improving the instrumentation we can then extract and understand intrinsic properties of the materials so that they may be further enhanced.At the end of the project we shall have established donor spins in isotopically engineered silicon as the forerunner material for quantum spintronics and demonstrated the essential components for a quantum spintronics device.

Planned Impact

The research proposed here addresses important questions of fundamental science as well as seeking to establish key components of an emerging quantum spintronics technology. We will build on our experience in materials science and quantum control techniques to embark on a series of experimental investigations using spins in condensed matter which lay previously well in the realm of isolated atomic physics. Such a step is critical for the exploitation of quantum coherence and entanglement within solid state devices. We will focus on silicon-based spin systems, which offer convenient integration within conventional technologies. Early applications of quantum spintronics include entanglement-enhanced magnetic field sensors for small changes in magnetic fields. With sufficient refinement, the technologies we establish could be developed towards applications in quantum information processing. Quantum information processing is already profoundly affecting the fields of computing and physics, possessing a novelty and a richness that suggests the likelihood of great unanticipated impact. Such promise has lead to significant funding around the world (e.g. major 5-years grants have recently been awarded to the value of 63M in Singapore, 30M in Canada, at institutions with which we are collaborating) and was highlighted in a US Federal Vision published earlier this year. The recent concept of a hybrid quantum device, a recurrent theme throughout this proposal, promises revolutionary advantages by allowing fast operation speeds (using electron spins) while having the ability to store quantum information for long times (using nuclear spins). This project fully embraces the emerging discipline of quantum information technology - a field of research which the British embassy in Tokyo has singled out as one in which is ripe for UK-Japan collaboration through their UK-Japan Quantum Information Workshop on 23-24 January 2009. Support for this cooperative program will directly address the acute need for increased mobility and exchange of researchers between the two countries which was identified in the report following this workshop. We have found that engaging 'weirdness' of quantum mechanics, and the technologies which it promises have the potential to excite the wider public. Dr Morton won the Cavendish Medal at SET for BRITAIN 2009 in the House of Commons, where he described his research to MPs. Drs Morton and Benjamin exhibited their work at the Royal Society 2008 Summer Science Exhibition. Dr Benjamin, with input from Dr Morton, has produced an award-winning series of podcasts on Quantum Nanotechnology on itunes.ox.ac.uk. We thus have considerable experience in the public engagement in science, and we shall look for new opportunities to share the excitement of the field of this project. Throughout the program we shall seek to educate policymakers in government, commerce, and industry, about the prospects for quantum technologies, and to using quantum nanoscience to help revive interest in the physical sciences in schools. Support of this program will also have a significant positive impact on the academic careers of the investigators, each of whom is at an early state in their careers, and significantly broaden the horizons of the UK post-doctoral researchers and students who will be able to experience a Japanese research environment and establish their own links with Japan.

Related Projects

Project Reference Relationship Related To Start End Award Value
EP/H025952/1 26/01/2010 30/06/2012 £60,937
EP/H025952/2 Transfer EP/H025952/1 31/12/2012 30/07/2013 £11,846
 
Description Our key *Objectives* of the grant have been met:

1. "To pursue ultra-long spin coherence times of donors in silicon", including developing control and measurement instrumentation, refine silicon materials, and assess bismuth for nuclear spin quantum memory. These goals have been achieved and presented in many of the publications listed (including Tyryshkin et al., Nature Materials (2012), Steger et al., Science (2012) and Saeedi et al., Science (2013)). In particular, they have led to world-record spin coherence times - the longest out of any spin in the solid state - and also initiated many studies on bismuth donors in silicon in international labs.

2. "To exploit donor electron and nuclear spins of donors in silicon for multimode microwave memories" starting by optimising spin coherence in Bi-doped 28Si (e.g. using atomic clock transitions), and ultimately transferring the state of a superconducting qubit, via a single microwave photon, into an ensemble of Bi donors. The first of these goals was presented in Wolfowicz et al., Nature Nanotechnology (2013) and showed for the first time that atomic clock transitions which were inherently insensitive to small changes in magnetic field could be accessed for donors in silicon, leading to dramatic enhancements in the coherence time of donors in either natural silicon, or enriched 28-silicon material. The ultimate goal of this workpackage (to transfer the state of a superconducting qubit to/from an ensemble of Bi donors) is still being actively pursued and we have very recently obtained the breakthrough result of coupling Bi donors to a superconducting resonator in a dilution fridge at low magnetic field.

3. "Spin entanglement using donors in silicon" was fully demonstrated and reported in Simmons et al. Nature (2010). This received much attention in the popular press (including the New York Times) and also highlighted the power of global control in accurately manipulating 10 billion entangled spin pairs. The result was the first on-demand demonstration of entanglement within an ensemble of spins.

4 & 5. "To understand the spin coherence properties of donors at very low applied magnetic fields, and to transfer the techniques and materials developed into single- or few-donor devices, exploiting established collaborations" was realised, most notably through collaborations of both the UK and Japanese teams with UNSW in Australia, presented in papers such as Pla et al. Nature 2012 and 2013.

6. "Theory of spin decoherence mechanisms and mitigation and the controlled removal of an electron spin on nuclear coherence and entanglement" has also been presented in several of the publications listed, including for example Schaffry et al Phys Rev Lett (2010).

Finally, the overarching aim of this grant to foster collaboration between groups in the UK and Japan has been fully realised, with many bilateral exchanges between the UK groups and Keio group and a particular emphasis on early career researchers such as PhD students and post-docs. We organised a joint international workshop in London on February 2013 to mark the end of the official grant, but the collaboration, exchange of researchers and joint publications are ongoing.

(Note: This is the same summary as for EP/H025952/2 as this is the same award which was moved from Oxford to UCL when I changed my appointment)
Exploitation Route The results of this award have been very actively presented in publications (including many high-impact journals aimed a broad readerships) as well as invited talks. They will impact the academic community through informing choices on the optimal materials to use for quantum technologies, with a particular emphasis on isotopically enriched silicon-28 and the use of novel dopants such as bismuth.

Our results also highlight to policymakers and industry the opportunities of using silicon, the industrial standard material for conventional electronics, for the emerging quantum technologies. This has profound importance for the compatibility and integration of quantum and classical technologies. Our results informs choices about what materials infrastructure to invest in to accelerate the development of quantum technologies, so that companies and/or countries can look to maintain or achieve a leading position in developing such technologies.
Sectors Digital/Communication/Information Technologies (including Software),Electronics

 
Description The collaboration with Kohei Itoh's group at Keio University, supported by this grant, began demonstrating the key advantages of isotopic engineering of silicon to obtain the longest possible spin coherence lifetimes and control fidelities. This has had a major effect in the direction of research around the world, with a much greater focused placed on isotopically enriched silicon-28, both for donor- and quantum-dot -based approaches to silicon quantum technologies. This has affected research directions in academia (e.g. UNSW in Australia), and private and government labs (e.g. Sandia National Labs, Hughes Research Labs). More and more groups are now focusing on ways to obtain isotopically enriched 28Si precursor gases and grow isotopically enriched material. There have also been indirect impacts in areas such as the Avogadro project, which seeks to create a new standard for the kilogram using isotopically enriched 28Si. By making excellent use of this material, the results from this grant have helped make the case for an new Avogadro project providing 28Si both for metrology and for quantum technologies. (Note: This is the same summary as for EP/H025952/2 as this is the same award which was moved from Oxford to UCL when I changed my appointment)
First Year Of Impact 2012
Sector Digital/Communication/Information Technologies (including Software),Electronics
 
Description EU Quantum Technology Initiative - Towards a Quantum Technology 'Flagship'
Geographic Reach Europe 
Policy Influence Type Participation in a national consultation
 
Description UK Quantum Technology Initiative
Geographic Reach National 
Policy Influence Type Participation in a national consultation
Impact Raise the profile of quantum technology and helped bring about a national UK initiative in quantum technology, with (amongst other things) focus on training a skilled workforce in quantum information. There is also the potential for UK economic impact further down the line.
 
Description CDT (Delivering Quantum Technologies)
Amount £5,410,603 (GBP)
Funding ID EP/L015242/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Academic/University
Country United Kingdom
Start 04/2014 
End 09/2022
 
Description ERC Starter Grant
Amount € 1,875,550 (EUR)
Funding ID ASCENT 
Organisation European Research Council (ERC) 
Sector Public
Country European Union (EU)
Start 12/2011 
End 11/2016
 
Description Marie Curie Fellowship (Eva Dupont-Ferrier)
Amount € 180,000 (EUR)
Organisation European Commission 
Department Horizon 2020
Sector Public
Country European Union (EU)
Start 03/2016 
End 02/2018
 
Description Marie Curie Fellowship (Jarryd Pla)
Amount € 144,044 (EUR)
Funding ID QURAM 
Organisation European Commission 
Department Seventh Framework Programme (FP7)
Sector Public
Country European Union (EU)
Start 03/2014 
End 02/2016
 
Description QT Skills Hub
Amount £3,597,372 (GBP)
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Academic/University
Country United Kingdom
Start 04/2016 
End 03/2021
 
Description Royal Society Research Grant
Amount £50,000 (GBP)
Funding ID RG090440 
Organisation The Royal Society 
Sector Academic/University
Country United Kingdom
Start 04/2010 
End 03/2012
 
Description Royal Society URF
Amount £496,000 (GBP)
Funding ID UF0763418 
Organisation The Royal Society 
Sector Academic/University
Country United Kingdom
Start 10/2008 
End 09/2013
 
Description Royal Society URF (extension)
Amount £442,388 (GBP)
Funding ID UF120062 
Organisation The Royal Society 
Sector Academic/University
Country United Kingdom
Start 10/2013 
End 09/2016
 
Description Hitachi Cambridge Laboratory 
Organisation Hitachi Cambridge Laboratory
Country United Kingdom 
Sector Private 
PI Contribution We have brought our expertise in the coherent control of spins, including spins in silicon, and in the optical measurement of spins using donor-bound exciton transitions
Collaborator Contribution Hitachi Cambridge Lab are co-funding a PhD student working on silicon quantum devices, and have provided access to millikelvin measurement facilities to researchers in my group, as well as training in the development of RF-reflectometry readout of devices.
Impact Charge dynamics and spin blockade in a hybrid double quantum dot in silicon M Urdampilleta, A Chatterjee, CC Lo, T Kobayashi, J Mansir, S Barraud, AC Betz, S Rogge, MF Gonzalez-Zalba, JJL Morton Phys Rev X 5 031024 (2015) Hybrid optical-electrical detection of donor electron spins with bound excitons in Si CC Lo, M Urdampilleta, P Ross, MF Gonzalez-Zalba, J Mansir, SA Lyon, MLW Thewalt, JJL Morton Nature Materials 14 490 (2015)
Start Year 2015
 
Description Hitachi Cambridge Laboratory / Fernando Gonzalez-Zalba 
Organisation Hitachi Cambridge Laboratory
Country United Kingdom 
Sector Private 
PI Contribution Bringing expertise in silicon spin qubits and quantum information; Measurement infrastructure at UCL for measuring silicon quantum devices and spin qubits and mK temperatures
Collaborator Contribution Co-funding 2 PhD students; Co-supervising both students; Presenting talks to my research group and UCLQ more widely giving industrial perspective; hosting students in Hitachi Cambridge Lab for extended research visits (6-10 weeks) with access to milliKelvin measurement facilities
Impact EU funding proposals: 1) MOS-QUITO project (€3M, awarded April 2016); 2) QT Flagship proposal (€10M, under review)
Start Year 2015
 
Description IMEC 
Organisation Interuniversity Micro-Electronics Centre
Country Belgium 
Sector Multiple 
PI Contribution We have brought our expertise in the design and measurement of silicon quantum devices
Collaborator Contribution IMEC are providing cutting-edge CMOS devices with high-yield, high-purity and small feature sizes. The aim is to jointly develop CMOS-based quantum devices for implementing spin qubits in silicon.
Impact EU funding proposals: QT Flagship proposal (€10M, under review)
Start Year 2016
 
Description Kohei Itoh, Keio University 
Organisation Keio University
Country Japan 
Sector Academic/University 
PI Contribution Expertise in pulsed electron spin resonance and quantum information
Collaborator Contribution Expertise in low-field electrically detected magnetic resonance (EDMR) and isotopically enriched silicon material
Impact 12 joint publications since 2010, including ones in Phys Rev Lett, Nature, Nature Materials and Nature Communications Over 10 bilateral exchanges of young researchers, including PhD students
Start Year 2010
 
Description Mike Thewalt, Simon Fraser Unversity 
Organisation Simon Fraser University
Country Canada 
Sector Academic/University 
PI Contribution Expertise in pulsed magnetic resonance, quantum information, spin decoherence and dynamical decoupling
Collaborator Contribution Expertise in optical spectroscopy of donors, including donor bound excitons, and access to highly enriched 28-silicon material
Impact 15 joint publications since 2010, including two in Science, one in Nature, four in Nature-family journals and two in Phys Rev Lett.
Start Year 2010
 
Description NPL 
Organisation NPL Ltd
PI Contribution Bringing expertise in silicon spin qubits and quantum information; Measurement infrastructure at UCL for measuring silicon quantum devices and spin qubits and mK temperatures
Collaborator Contribution Co-funding a PhD student; Co-supervising student; Presenting talks to UCLQ more widely giving industrial perspective; hosting student at NPL Lab for extended research visits (6-10 weeks) with access to milliKelvin measurement facilities
Impact N/A
Start Year 2017
 
Description NPL 
Organisation National Physical Laboratory
Department Time, Quantum and Electromagnetics Division
Country United Kingdom 
Sector Public 
PI Contribution We have brought our expertise in highly coherent spins in silicon and rare-earth spins in YSO, including spin coherence times and decoherence mechanisms, as well as expertise in NbN resonator fabrication.
Collaborator Contribution The NPL team have cutting-edge facilities for the measurement of superconducting resonators at mK temperatures, as well as expertise in the design of such structures and coupling them to implanted spins. They are co-funding a PhD student in my group and providing access to specialised measurement infrastructure.
Impact N/A
Start Year 2016
 
Description Patrice Bertet, CEA Saclay 
Organisation Saclay Nuclear Research Centre
Country France 
Sector Public 
PI Contribution Expertise in donor spins in silicon, specifically bismuth-doped silicon. Jarryd Pla, a post-doctoral fellow in the group, has made regular visits to Saclay to fabricate structures and perform measurements.
Collaborator Contribution Expertise in circuit quantum electrodynamics using superconducting resonators and superconducting qubits.
Impact Controlling spin relaxation with a cavity A Bienfait, JJ Pla, Y Kubo, X Zhou, M Stern, CC Lo, CD Weis, T Schenkel, D Vion, D Esteve, JJL Morton and P Bertet, Nature 531, 74 (2016) Reaching the quantum limit of sensitivity in electron spin resonance A Bienfait, JJ Pla, Y Kubo, M Stern, X Zhou, CC Lo, CD Weis, T Schenkel, MLW Thewalt, D Vion, D Esteve, B Julsgaard, K Moelmer, JJL Morton and P Bertet, Nature Nanotechnology 11, 253 (2015)
Start Year 2013
 
Description Philippe Goldner 
Organisation National School of Chemistry of Rennes
Department Chemistry Research Institute Paris
PI Contribution We have brought expertise in pulsed electron spin resonance, coherent state transfer between electron and nuclear spins, and decoherence mechanisms
Collaborator Contribution They made unique samples of isotopically-engineered rare earth dopants in YSO, and participated in the measurements in our laboratory
Impact Coherent storage of microwave excitations in rare-earth nuclear spins G Wolfowicz, H Maier-Flaig, R Marino, A Ferrier, H Vezin, JJL Morton, P Goldner Phys Rev Lett 114 170503 (2015)
Start Year 2012
 
Description Ren Bau Liu (Hong Kong) 
Organisation Chinese University of Hong Kong
Country Hong Kong 
Sector Academic/University 
PI Contribution Expertise in experimental measurements of spin decoherence of donors in silicon
Collaborator Contribution Expertise in the theory of open quantum systems, and coupling to spin baths
Impact Uncovering many-body correlations in nanoscale nuclear spin baths by central spin decoherence, W-L Ma, G Wolfowicz, N Zhao, S-S Li, JJL Morton, R-B Liu Nature Communications 5 4822 (2014) Classical nature of nuclear spin noise near clock transitions of Bi donors in Si W-L Ma, G Wolfowicz, S-S Li, J J L Morton, R-B Liu Phys Rev B 92 161403(R) (2015)
Start Year 2013
 
Title Surface code quantum computer architecture using shuttling spins 
Description Architecture for a fault-tolerant quantum computer based on donor spins in silicon 
IP Reference WO2015124950 
Protection Patent granted
Year Protection Granted 2015
Licensed Yes
Impact N/A
 
Company Name Q & I Ltd 
Description Quantum technology consultancy 
Year Established 2015 
Impact N/A
Website http://www.qandi.co.uk
 
Description BBC World Service 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? Yes
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Interview on quantum mechanical effects in a likely mechanisms for how birds 'see' magnetic fields.

BBC have been in touch for further information on how this field has developed as it is an area which attracted considerable interest from the public.
Year(s) Of Engagement Activity 2013
 
Description IEEE Spectrum Article 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Overview article on silicon-based quantum computing aimed at wide electronics engineering community. IEEE Spectrum has a circulation of over 380,000 engineers worldwide.

After this was published, companies such as BT made contact to explore potential collaborations
Year(s) Of Engagement Activity 2014
 
Description Inv Talk - 2016 - CWTEC 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Industry/Business
Results and Impact Invited presentation entitled "What is a universal quantum computer and how do I build one" delivered at the CW-TEC (Cambridge Wireless Technology) 2016 event. This event is addressed primarily at industry and academia in the sectors of wireless communication, and led to discussions on the likely timescales of commercial quantum computers.
Year(s) Of Engagement Activity 2016
 
Description NPR Interview 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Interview on National Public Radio (NPR), USA on "Spintronics: A New Way To Store Digital Data".

Active discussed thread on NPR website for this radio programme discussing future technologies
Year(s) Of Engagement Activity 2010
 
Description Physics Teacher Training 2016 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Schools
Results and Impact 15 teachers of Physics at A/AS-level attended a talk I had prepared on how to present some of the latest developments in measurements of quantum dots and development of a new current standard in terms of A-level physics, providing ideas for how they can cover this recent work in their classrooms.
Year(s) Of Engagement Activity 2016
 
Description Quantum of Spin 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? Yes
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact Quantum of Spin was an exhibit on our research on using spins for quantum technologies, reaching over 10,000 members of the public. The hand's on exhibits including a real MRI system for which they were able to make and image "phantoms", resonant experiments and illustrations of superposition and entanglement.

HRH The Duke of York developed an interested in quantum technologies following a discussion at this exhibit, which led to two meetings at Buckingham Palace on Quantum Technologies
Year(s) Of Engagement Activity 2012
 
Description School visit (Osaka high school) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Schools
Results and Impact Talk to Japanese high-school students on introduction to quantum computing

It was clear this was a very different style of teaching than the students were used to, but they seemed to enjoy the challenging ideas
Year(s) Of Engagement Activity 2010
 
Description School visit (St Pauls Girls School) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact Talk on weirdness of quantum mechanics and applications in technologies

Students requested internships in my lab
Year(s) Of Engagement Activity 2013