Frontiers in research of emergent materials
Lead Research Organisation:
University of Oxford
Department Name: Oxford Physics
Abstract
This proposal aims to facilitate effective interaction between a range of scientists including experimental and theoretical physicists, chemists and material scientists to identify the organizing principles responsible for the remarkable range of quantum phases observed in strongly correlated electron systems, to predict and explore new avenues for research and discover novel functional materials. Funding is sought for organizing workshops, facilitating exchange visits, setting up a visiting programme for international leading researchers and for seeding projects related to discovery of novel materials.
Planned Impact
While future scientific endeavor is difficult to predict in advance, the discovery of unexpected physics displayed by strongly correlated systems with markedly improved multifunctional properties compared with widely used semiconductors will one day have a dramatic effect on our lives. Emergent phenomena, in which the correlated behavior of many particles leads to collective new properties, are of great significance across a broad range of areas in science. However, the objective is to tailor a material (starting with its chemical composition, constituent phases) in order to obtain a desired set of properties suitable for a given application. Today technological advances are based on semiconductor physics due to their high degree of precise processing. However, if the same can be achieved for strongly correlated materials which have multifunctional and unique properties, such as superconductivity and magnetism. not found in semiconductors, would open up remarkable technological possibilities.
People |
ORCID iD |
| Amalia Coldea (Principal Investigator) |
Publications
Alexander-Webber JA
(2018)
Multi-band magnetotransport in exfoliated thin films of Cu x Bi2Se3.
in Journal of physics. Condensed matter : an Institute of Physics journal
Blake S
(2016)
de Haas-van Alphen study of role of 4 f electrons in antiferromagnetic CeZn 11 as compared to its nonmagnetic analog LaZn 11
in Physical Review B
Blake S
(2015)
Fermi surface of IrTe 2 in the valence-bond state as determined by quantum oscillations
in Physical Review B
Bristow M
(2023)
Multiband description of the upper critical field of bulk FeSe
in Physical Review B
Bristow M
(2020)
Competing pairing interactions responsible for the large upper critical field in a stoichiometric iron-based superconductor CaKFe 4 As 4
in Physical Review B
Bristow M
(2020)
Anomalous high-magnetic field electronic state of the nematic superconductors FeSe 1 - x S x
in Physical Review Research
Coldea A
(2013)
Iron-based superconductors in high magnetic fields
in Comptes Rendus Physique
Coldea A
(2018)
The Key Ingredients of the Electronic Structure of FeSe
in Annual Review of Condensed Matter Physics
Coldea A
(2019)
Evolution of the low-temperature Fermi surface of superconducting FeSe1-xSx across a nematic phase transition
in npj Quantum Materials
Coldea A
(2014)
Cascade of field-induced magnetic transitions in a frustrated antiferromagnetic metal
in Physical Review B
| Description | The aim of this proposal was to facilitate the effective interaction between a range of scientists including experimental and theoretical physicists, chemists and material scientists working on quantum phases observed in strongly correlated. This has been achieved by organizing an annual symposium dedicated to quantum materials (Quantum Symposium on Quantum Materials), visits of international leading researchers to enhanced our research, developing new quantum materials and establishing new research collaborations. |
| Exploitation Route | Generate new collaborations, new directions, future funding (Oxford Quantum Materials Platform Grant and Oxford Centre for Applied Superconductivity), interaction with industry via the Oxford Centre for Applied Superconductivity, organization of the international conference Quantum Materials Symposium (2019) (https://qms.web.ox.ac.uk/home). |
| Sectors | Education,Electronics,Energy,Other |
| URL | https://www2.physics.ox.ac.uk/research/quantum-materials/group-activities/oxford-symposium-on-quantum-materials |
| Description | This funding has enhanced the interdisciplinary interactions and community building between physicists, chemists, materials scientists and theoreticians in and around Oxford in order to advance the science and promote direct collaboration between groups interested in novel quantum materials and phenomena. The Oxford Symposium on Quantum Materials has become an important annual interdisciplinary forum (~100 participants). Furthermore, the profile of this event has brought to Oxford the international Quantum Materials Symposium 2019. These forums have provided the platform for new collaborations and interactions among the participants as well as with policy makers, publishers and industry. More details are available at https://qms.web.ox.ac.uk/. Beneficiaries: Academics, researchers and students. Contribution Method: This meeting has provided the necessary ingredients towards collaborations in overlapping research areas with the aim to advance knowledge, train scientists and open up new avenues of research by collaboration. |
| First Year Of Impact | 2011 |
| Sector | Education,Energy,Other |
| Impact Types | Cultural,Societal,Policy & public services |
| Description | Oxford Quantum Materials Platform Grant |
| Amount | £1,736,109 (GBP) |
| Funding ID | EP/M020517/1 |
| Organisation | Engineering and Physical Sciences Research Council (EPSRC) |
| Sector | Public |
| Country | United Kingdom |
| Start | 04/2015 |
| End | 03/2020 |
| Title | Anomalous high-magnetic field electronic state of the nematic superconductors FeSe1-xSx |
| Description | These data are raw data as part of the manuscript: "Anomalous high-magnetic field electronic state of the nematic superconductors FeSe1-xSx" (arXiv:1904.02522) https://arxiv.org/abs/1904.02522. The manuscript will be published as an Article in Physical Review Research 2020. The magnetotransport data were collected using high magnetic fields with Helium 3 cryostats either in Nijmegen up to 38T , Tallahahassee up to 45T and pulsed fields close to 65T in Toulouse. The data were collected using lock-in amplifiers. The data here are part of the figures presented in the manuscript were detailed figure captions are provided. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2020 |
| Provided To Others? | Yes |
| Impact | Understanding superconductivity requires detailed knowledge of the normal electronic state from which it emerges. A nematic electronic state that breaks the rotational symmetry of the lattice can potentially promote unique scattering relevant for superconductivity. Here, we investigate the normal transport of superconducting FeSe1-xSx across a nematic phase transition using high magnetic fields up to 69 T to establish the temperature and field-dependencies. We find that the nematic state is an anomalous non-Fermi liquid, dominated by a linear resistivity at low temperatures that can transform into a Fermi liquid, depending on the composition x and the impurity level. Near the nematic end point, we find an extended temperature regime with T1.5 resistivity. The transverse magnetoresistance inside the nematic phase has as a H1.55 dependence over a large magnetic field range and it displays an unusual peak at low temperatures inside the nematic phase. Our study reveals anomalous transport inside the nematic phase, driven by the subtle interplay between the changes in the electronic structure of a multi-band system and the unusual scattering processes affected by large magnetic fields and disorder |
| URL | https://ora.ox.ac.uk/objects/uuid:37ed680b-6992-4d97-b929-c9af2559a029 |
| Title | Evidence for unidirectional nematic bond ordering in FeSe |
| Description | These data are related to the paper https://arxiv.org/abs/1603.04545 to be published in Physical Review B in 2016. Raw data files are in .nxs format, which are standard HDF5 format files created at I05 at diamond. PDF figures have some basic description in the filename. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2016 |
| Provided To Others? | Yes |
| Impact | n/a |
| Title | FeSe_magneotransport_Watson_PRL_2015 |
| Description | These data constitute the data presented in the plots of Figures 1 and 2 in "Dichotomy between the Hole and Electron Behavior in the Multiband FeSe Probed by Ultrahigh Magnetic Fields" (Watson, PRL, 2015). The figures were created in Origin, but can be reproduced in any graphing software that can import standard ASCII files. The resistivity and Hall effect data has been scaled by the sample geometry into resistivty (not resistance) units. The data were collected in the Clarendon Laboratory, Oxford University and at the EMFL high magnetic field facilities in Toulouse. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2015 |
| Provided To Others? | Yes |
| Impact | n/a |
| Title | Magnetotransport CuxBi2Se3 |
| Description | These data were created by recording the transport behaviour on thin flakes devices at low temperatures and in magnetic field. These are all DAT files easily readable. We report magnetotransport studies in thin (<100nm) exfoliated films of CuxBi2Se3 and we detect an unusual electronic transition at low temperatures. Bulk crystals show weak superconductivity with Tc~3.5K and a possible electronic phase transition around 200K. Following exfoliation, superconductivity is supressed and a strongly temperature dependent multi-band conductivity is observed for T<30K. This transition between competing conducting channels may be enhanced due to the presence of electronic ordering, and could be affected by the presence of an effective internal stress due to Cu intercalation. By fitting to the weak antilocalisation conductivity correction at low magnetic fields we confirm that the low temperature regime maintains a quantum phase coherence length Lphiv> > 100nm indicating the presence of topologically protected surface states. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2018 |
| Provided To Others? | Yes |
| Impact | Publication: Multi-band magnetotransport in exfoliated thin films of CuxBi2Se3, by J A Alexander-Webber, J Huang, J Beilsten-Edmands, P Cermák, C Drašar, R J Nicholas and A I Coldea Published 16 March 2018, Journal of Physics: Condensed Matter, Volume 30, Number 15. This work has opened up the design of devices using thin flakes of single crystals to study they magnetotransport and topological signatures. |
| URL | https://ora.ox.ac.uk/objects/uuid:f9dbd74f-1f42-4d45-a236-456bee6d8d1e |
| Title | Quantum oscillations in the nematic superconductors FeSe1-xSx |
| Description | These are the Raw data used to generate the figures related to the publication: "Evolution of the Fermi surface of the nematic superconductors FeSe1-xSx" by A. I. Coldea et al. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2018 |
| Provided To Others? | Yes |
| Impact | The existence of a nematic phase transition in iron-chalcogenide superconductors poses an intriguing question about its impact on superconductivity. To understand the nature of this unique quantum phase transition, it is essential to study how the electronic structure changes across this transition at low temperatures. Here, we investigate the evolution of the Fermi surfaces and electronic interactions across the nematic phase transition of FeSe1-xSx using Shubnikov-de Haas oscillations in high magnetic fields up to 45 T in the low temperature regime down to 0.4 K. Most of the Fermi surfaces of FeSe1-xSx monotonically increase in size except for a prominent low frequency oscillation associated with a small, but highly mobile band, which disappears at the nematic phase boundary near x ~ 0.17, indicative of a topological Lifshitz transition. The quasiparticle masses are larger inside the nematic phase, indicative of a strongly correlated state, but they become suppressed outside it. The experimentally observed changes in the Fermi surface topology, together with the varying degree of electronic correlations, will change the balance of electronic interactions in the multi-band system FeSe1-xSx and promote different kz-dependent superconducting pairing channels inside and outside the nematic phase. |
| URL | https://ora.ox.ac.uk/objects/uuid:dad66609-f461-4f7d-9373-190e309a2ed9 |
| Title | Quenched nematic criticality separating two superconducting domes in an iron-based superconductor under pressure |
| Description | The data reflect experimental transport and tunnel diode oscillator measurements collected in zero field or in magnetic fields either in Oxford or at the NHMFL Tallahassee Florida. Measurements were performed at different applied pressuresusing a piston pressure cell. The data set contain raw data plotted in Figures of the manuscript arXiv:1902.11276 (https://arxiv.org/abs/1902.11276). |
| Type Of Material | Database/Collection of data |
| Year Produced | 2019 |
| Provided To Others? | Yes |
| Impact | The nematic electronic state and its associated critical fluctuations have emerged as a potential candidate for the superconducting pairing in various unconventional superconductors. However, in most materials their coexistence with magnetically ordered phases poses a significant challenge in determining their importance. Here, by combining chemical and hydrostatic physical pressure in FeSe0.89S0.11, we access a nematic quantum phase transition isolated from any other competing magnetic phases. From quantum oscillations in high magnetic fields, we trace the evolution of the Fermi surface and electronic correlations as a function of applied pressure and detect a Lifshitz transition that separates two distinct superconducting regions. One emerges from the nematic phase with a small Fermi surface and strong electronic correlations, while the other one has a large Fermi surface and weak correlations that promotes nesting and stabilization of a magnetically ordered phase at high pressures. The absence of mass divergence at the nematic quantum phase transition suggests that the nematic fluctuations could be quenched by the strong coupling to the lattice or local strain effects. A direct consequence is the weakening of superconductivity at the nematic quantum phase transition in the absence of magnetically driven fluctuations. |
| URL | https://ora.ox.ac.uk/objects/uuid:b739b72e-b6a4-4c4b-bc5f-6848546ae274 |
| Title | Simulations_AMRO_hexagonal |
| Description | These data were created using Matlab over the last few years. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2016 |
| Provided To Others? | Yes |
| Impact | n/a |
| URL | https://ora.ox.ac.uk/objects/uuid:ffe7d5fe-00da-497e-b94c-3735eb2edf7d |
| Title | Suppression of electronic correlations by chemical pressure from FeSe to FeS |
| Description | ARPES data were created at the Diamod Light Source and transport data were collected in Oxford. These data are part of the publication with the same title to appear in Phys Rev B, Rapid Communication 2017. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2017 |
| Provided To Others? | Yes |
| Impact | Iron-based chalcogenides are complex superconducting systems in which orbitally-dependent electronic correlations play an important role. Here, using high-resolution angle-resolved photoemission spectroscopy, we investigate the effect of these electronic correlations outside the nematic phase in the tetragonal phase of superconducting FeSe1-xSx (x = 0; 0:18; 1). With increasing sulfur substitution, the Fermi velocities increase significantly and the band renormalizations are suppressed towards a factor of 1.5-2 for FeS. Furthermore, the chemical pressure leads to an increase in the size of the quasi-two dimensional Fermi surface, compared with that of FeSe, however, it remains smaller than the predicted one from first principle calculations for FeS. Our results show that the isoelectronic substitution is an effective way to tune electronic correlations in FeSe1-xSx, being weakened for FeS with a lower superconducting transition temperature. This suggests indirectly that electronic correlations could help to promote higher-Tc superconductivity in FeSe. |
| URL | https://ora.ox.ac.uk/objects/uuid:6423d3c7-d4a4-443f-9fbc-b2ff254863bc |
| Title | Suppression of orbital ordering by chemical pressure in FeSe1-xSx |
| Description | This data was collected using Diamond Light Source, beamline i05. Some of the raw data is in the nxs format of the beamline. Data were analyzed using Matlab and Origin. Each folder contains the data in different figure of the paper posted on archive: http://arxiv.org/abs/1508.05016. We report a high-resolution angle-resolved photoemission spectroscopy study of the evolution of the electronic structure of FeSe1-xSx single crystals. Isovalent S substitution onto the Se site constitutes a chemical pressure which subtly modifies the electronic structure of FeSe at high temperatures and induces a suppression of the tetragonal-symmetry-breaking structural transition temperature from 87 to 58 K for x = 0.15. With increasing S substitution, we find smaller splitting between bands with dyz and dxz orbital character and weaker anisotropic distortions of the low-temperature Fermi surfaces. These effects evolve systematically as a function of both S substitution and temperature, providing strong evidence that an orbital ordering is the underlying order parameter of the structural transition in FeSe1-xSx . Finally, we detect the small inner hole pocket for x = 0.12, which is pushed below the Fermi level in the orbitally ordered low-temperature Fermi surface of FeSe. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2015 |
| Provided To Others? | Yes |
| Impact | Understanding of electronic structure and superconductivity of FeSe1-xSx |
| URL | https://ora.ox.ac.uk/objects/uuid:be7c2ba3-b358-4840-b77e-7a8b70d32340 |
| Title | de Haas--van Alphen study of the role of 4f electrons in antiferromagnetic CeZn11 as compared to its nonmagnetic analogue LaZn11 |
| Description | These are the data generated to produce the publication entitled "de Haas--van Alphen study of the role of 4f electrons in antiferromagnetic CeZn11 as compared to its nonmagnetic analogue LaZn11" by S. F. Blake, H. Hodovanets, A. McCollam, S. L. Bud'ko, P. C. Canfield, and A. I. Coldea published in Physical Review B. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2016 |
| Provided To Others? | Yes |
| Impact | We present a de Haas-van Alphen study of the Fermi surface of the low temperature antiferromagnet CeZn11 and its non-magnetic analogue LaZn11, measured by torque magnetometry up to fields of 33T and at temperatures down to 320 mK. Both systems possess similar de Haas-van Alphen frequencies, with three clear sets of features - ranging from 50T to 4kT - corresponding to three bands of a complex Fermi surface, with an expected fourth band also seen weakly in CeZn11. The effective masses of the charge carriers are very light (<1 me) in LaZn11 but a factor of 2 - 4 larger in CeZn11, indicative of stronger electronic correlations. We perform detailed density functional theory (DFT) calculations for CeZn11 and find that only DFT+U calculations with U=1.5 eV, which localize the 4f states, provide a good match to the measured de Haas-van Alphen frequencies, once the presence of magnetic breakdown orbits is also considered. Our study suggests that the Fermi surface of CeZn11 is very close to that of LaZn11 being dominated by Zn 3d, as the Ce 4f states are localised and have little influence on its electronic structure, however, they are responsible for its magnetic order and contribute to enhance electronic correlations. |
| URL | https://ora.ox.ac.uk/objects/uuid:e3251001-47a6-405d-9359-02bec24ba363 |
| Description | ARPES |
| Organisation | Diamond Light Source |
| Country | United Kingdom |
| Sector | Private |
| PI Contribution | Performing, analyzing and publishing work together. We provided samples and developed our own software to analyze ARPES data on Fe based superconductors. |
| Collaborator Contribution | Provide technical help and complementary analysis tools. |
| Impact | Beamtime awarded on the Diamond I05 beamline. Training of a PhD student which now is employed by the Diamond Light Source Title: Emergence of the nematic electronic state in FeSe Author(s): Watson, M. D.; Kim, T. K.; Haghighirad, A. A.; et al. Source: Physical Review B Volume: 91 Issue: 15 Published: 2015 DOI: 10.1103/PhysRevB.91.155106 Title: Suppression of orbital ordering by chemical pressure in FeSe1-xSx Author(s): Watson, M. D.; Kim, T. K.; Haghighirad, A. A.; et al. Source: Physical Review B Volume: 92 Issue: 12 Published: 2015 DOI: 10.1103/PhysRevB.92.121108 |
| Start Year | 2014 |
| Description | DFT collaboration |
| Organisation | Goethe University Frankfurt |
| Country | Germany |
| Sector | Academic/University |
| PI Contribution | DFT and DMFT calculations |
| Collaborator Contribution | Experimental and computational studies to understand the electronic structure and electronic correlations of FeSe measured using angle-resolved photoemission spectroscopy. |
| Impact | Formation of Hubbard-like bands as a fingerprint of strong electron-electron interactions in FeSe Matthew D. Watson, Steffen Backes, Amir A. Haghighirad, Moritz Hoesch, Timur K. Kim, Amalia I. Coldea, and Roser Valentí Phys. Rev. B 95, 081106(R) - Published 22 February 2017 |
| Start Year | 2011 |
| Description | Oxford Quantum Materials |
| Organisation | University of Oxford |
| Department | Quantum Materials |
| Country | United Kingdom |
| Sector | Academic/University |
| PI Contribution | Oxford Quantum Materials Platform Grant |
| Collaborator Contribution | Oxford Quantum Materials Platform Grant |
| Impact | Oxford Quantum Materials Platform Grant (1,736,109) Physics, Materials, Chemistry Recent relevant publication: Ideal Weyl semimetal induced by magnetic exchange J.-R. Soh, F. de Juan, M. G. Vergniory, N. B. M. Schröter, M. C. Rahn, D. Y. Yan, J. Jiang, M. Bristow, P. Reiss, J. N. Blandy, Y. F. Guo, Y. G. Shi, T. K. Kim, A. McCollam, S. H. Simon, Y. Chen, A. I. Coldea, and A. T. Boothroyd Phys. Rev. B 100, 201102(R) - Published 13 November 2019 |
| Start Year | 2013 |
| Description | UCLA Collaboration |
| Organisation | University of California, Los Angeles (UCLA) |
| Country | United States |
| Sector | Academic/University |
| PI Contribution | Experimental study and provision of materials SrAg4As2 |
| Collaborator Contribution | Experimental study and provision of materials SrAg4As2 |
| Impact | Significant change in the electronic behavior associated with structural distortions in monocrystalline SrAg4As2 Bing Shen, Eve Emmanouilidou, Xiaoyu Deng, Alix McCollam, Jie Xing, Gabriel Kotliar, Amalia I. Coldea, and Ni Ni Phys. Rev. B 98, 235130 - Published 13 December 2018 |
| Start Year | 2016 |
| Description | OUTREACH Schools |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | Local |
| Primary Audience | Schools |
| Results and Impact | Talks and demonstrations to primary school children The children got excited about the science presented. Parents confirmed the children interest in the presented talk and demonstrations. |
| Year(s) Of Engagement Activity | 2011,2012,2013,2014 |