Superconductivity and magnetism at and above 38K in molecular materials
Lead Research Organisation:
Durham University
Department Name: Chemistry
Abstract
Metals are used for electricity transmission, but energy is lost as heat because of electrical resistance. Superconductors have no electrical resistance and can carry electricity without losing energy, so finding superconductors which work at as high a temperature as possible is important. Most superconductors have simple structures built from atoms, but recently superconductors made from molecules arranged in regular solid structures have been found. Recent work by the proposing groups on molecular fulleride-based systems led to the discovery of the highest working temperature (at 38 K) for a molecular superconductor. We found that the electronic ground state which is in competition with superconductivity is magnetically ordered - this ordering also occurs at a very high temperature (46K) for a material where the active electrons are in orbitals of s/p parentage. We showed how the exact arrangement of the C60 molecules in the solid with stoichiometry Cs3C60 can be controlled to switch on the zero-resistance superconducting state from the insulating magnetically ordered state. In this project we will exploit the newly presented opportunities arising from these discoveries. We will identify the factors responsible for determining whether superconducting or magnetic ground states are adopted in new fulleride systems. We will develop new structural families of molecular, s/p electron-based superconductors and magnets with enhanced properties, controlled in an understandable manner by crystal symmetry, orbital degeneracy and lattice packing. In order to achieve this, we will use focussed solution-based synthetic protocols that we have pioneered, combined with structural and physical property measurements at ambient and high pressure and high-level electronic structure calculations. The project will explore unique aspects of the behavior of correlated electrons in solids i.e. electrons whose behavior is determined by their mutual Coulomb repulsion. This is one of the most important contemporary problems in condensed matter science. The high molecular and lattice symmetry of fullerene-based solids offers an opportunity to study strongly correlated electrons under conditions that are qualitatively different from previously studied materials, and therefore to take our understanding of molecular superconductivity and magnetism and the metal-insulator transition to an unprecedentedly advanced stage. The programme exploits the complementary expertise of the two principal investigators and will lead to a new generation of novel fullerene-based molecular materials with unpredictable and theoretically challenging properties.
People |
ORCID iD |
Kosmas Prassides (Principal Investigator) |
Publications
Margadonna S
(2009)
Pressure evolution of the low-temperature crystal structure and bonding of the superconductor FeSe ( T c = 37 K )
in Physical Review B
Prassides K
(2010)
Superconductivity: Interfaces heat up.
in Nature materials
Rosseinsky MJ
(2010)
Materials science: Hydrocarbon superconductors.
in Nature
Serafin A
(2010)
Anisotropic fluctuations and quasiparticle excitations in FeSe 0.5 Te 0.5
in Physical Review B
Souliou S
(2011)
High-pressure Raman study of the Sm 2.75 C 60 fulleride
in High Pressure Research
Tamai A
(2010)
Strong electron correlations in the normal state of the iron-based FeSe0.42Te0.58 superconductor observed by angle-resolved photoemission spectroscopy.
in Physical review letters
Withers N
(2010)
Determined by distance
in Nature Chemistry
Description | Following the unveiling of the highest Tc (at 38 K) molecular superconductor known and the demonstration that superconductivity in this system emerges out of an antiferromagnetic insulator parent state, we have been successful in isolating a second polymorph of the key magnetic and superconducting composition, which allowed us to reveal the competition between these two cooperative electronic states when the same electronically active unit is arranged entirely differently in space - such a situation had been unprecedented in high-Tc superconductors in which only one arrangement of the electronically active units (typically a two-dimensional square lattice) is accessible.This work represents a corner-stone of high-Tc superconductivity and molecular magnetism with significant implications for many generic problems in condensed matter research on strongly correlated electron systems. |
Exploitation Route | The scientific developments have attracted a high level of interest from all involved in the synthesis, properties and device development of organic materials. The project has produced fundamental knowledge targeted at short-term beneficiaries in the academic chemistry, physics and materials science communities working on highly correlated electronic systems. The ramifications of correlated systems are widespread in superconductivity, magnetoresistance, metal- insulator transitions and non-linear optical phenomena, and the results of this work on topical aspects of the Mott-Hubbard insulator have a wide audience. |
Sectors | Education,Electronics,Energy |
Description | In furthering understanding of the key technological discipline of superconductivity |
First Year Of Impact | 2009 |
Sector | Education,Electronics,Energy |
Impact Types | Societal |
Description | European Commission (EC) |
Amount | £299,828 (GBP) |
Funding ID | 283214 LEMSUPER CP-FP |
Organisation | European Commission |
Sector | Public |
Country | European Union (EU) |
Start | 10/2011 |
End | 03/2015 |