Unconventional superconductors: new paradigms for new materials

Lead Research Organisation: University of Bristol
Department Name: Physics

Abstract

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Description This project has led to several important developments in the field of unconventional superconductivity which encompass, and indeed surpass, the original aims of the project, including:
1) A very good understanding of the physics of unconventional superconductivity in LaNiC2 and LaNiGa2. This field was wide open when the project started however as a result of this project we can now say these systems are perhaps the best-understood triplet superconductors. We now understand them as examples of a new class of Internally-antisymmetric Nonunitary Triplet (INT) superconductors characterised by broken time-reversal symmetry, a spontaneous magnetisation, and fully-gapped spectrum. This is now confirmed by numerous experiments that our theorist have suggested and helped to interpret and moreover there is now a first-principles theory with a single adjustable parameter which reproduces the experimental data remarkably well.
2) Discovery of signatures of broken time-reversal symmetry in additional materials including, among others, elemental Rhenium. This is incredibly suprising and it is unlikely that such result would have been obtained without the impetus given to the field by the present project.
3) A new proposal to apply topological superconductivity in energy applications. This is probably the first time an application of topological superconductivity outside the field of information processing has been proposed.
4) New tools for the prediction and analysis of experimental data on superconductors. In particular, the first-principles theory mentioned above provides a template for future theories of other unconventional superconductors capable to describing experimental data. We also published an extensive review paper on time reversal symmetry breaking in superconductors.
Exploitation Route Currently these results are of academic interest, and not yet linked to any possible or probably commercial impact in the near future
Sectors Other
 
Description RAL 
Organisation Science and Technologies Facilities Council (STFC)
Department ISIS Neutron and Muon Source
Country United Kingdom 
Sector Academic/University 
PI Contribution The grant is a linked grant with project partners in Bristol, University of Kent and at the ISIS facility at Rutherford Appleton Laboratory
Collaborator Contribution We have regular collaboration meetings and discuss ideas and results by email and Skype. Joint publications of results are made when appropriate.
Impact The papers linked to this grant are all a result of this collaboration, although individual paper authorships vary depending on contributions to each specific piece of work.
Start Year 2016
 
Description University of Kent team, led by Dr Jorge Quintanilla 
Organisation University of Kent
Department Department of Physics and Astronomy
Country United Kingdom 
Sector Academic/University 
PI Contribution This project is a linked EPSRC grant working as a collaboration between the Bristol and Kent groups. We have had several collaboration meetings and have already produced some joint publications.
Collaborator Contribution The theoretical work is divided up between the Bristol and Kent groups, with the Bristol group concentrating on ab initio electronic structure methods and the Kent group developing models. This involves close collaboration between both groups in terms of model building and verification by comparison to the ab initio calculations.
Impact Published joint papers are listed as outputs of the project.
Start Year 2016