Unit(s) of assessment: General Engineering
Research theme: Medical Technologies and Advanced Materials
School: School of Science and Technology
Superconductors are one of the most exciting and incredible materials that has ever been discovered. Superconductors can conduct huge electrical currents with no resistance which makes them ideal candidates for use as power transmission cables. Their ability to conduct huge electrical currents enables them to be used to produce powerful magnetic fields which has made MRI machines and the Large-Hadron Collider possible. Magnetic levitating trains have also been realised due to the unique properties of superconductors.
Reduced dimensionality semiconductors and superconductors are important for the further miniaturisation of electronic circuits. Recently, two-dimensional superconductors have been attracting growing interest in condensed matter physics and electronic device communities. Advances in fabrication techniques have enabled the manufacture of atomically thin layers grown by molecular beam epitaxy, heterogeneous interfaces, and field effect devices. These 2D systems are showing novel physical properties that are unparalleled in traditional 3D materials which make them promising for future applications in quantum computing.
Addressing the Challenge
Molecular materials offer ‘multifunctionality’ and ‘tunability’ which provides an advantage over traditional solids. We are using molecules as building blocks to form layered molecular materials, where each layer gives its own individual distinct property to the multifunctional material. We can also introduce combinations of properties into the same material that do not exist together in nature to explore their interplay – e.g. superconductivity, two-dimensionality, magnetism, chirality.
We can make atom-by-atom (or molecule-by-molecule) changes to the structure of the molecular material to fine tune the properties as desired. We can also chemically control the thickness of the layers to manipulate the 2D nature of the material and explore the effect that this has upon the superconducting behaviour.
This work is currently funded by:
Leverhulme Trust Project Grant: Chiral and Racemic 2D Superconductors, October 2019-September 2022.
The Royal Society, International Exchange, Chiral Magnetic 2-Dimensional Metals and Superconductors, December 2020-December 2022
Principal Investigator: Dr Lee Martin
Research Fellow: Dr Toby Blundell
PhD student: Ms Elizabeth Rusbridge
Making a Difference
The materials synthesised at NTU in this project are being studied by a number of collaborating research groups:
*Osaka University, Japan
*Hokkaido University, Japan
*University of Hyogo, Japan
*National Institute for Materials Science, Japan
*Institute for Molecular Science, Japan
*University of Tokyo, ISSP
*Clark University, USA
T. J. Blundell, M. Brannan, H. Nishimoto, T. Kadoya, J.-i. Yamada, H. Akutsu, Y. Nakazawa, L. Martin, Chiral Metal Down to 4.2K - a BDH-TTP Radical-Cation Salt with Spiroboronate Anion B(2-chloromandelate)2−, Chem. Commun., 2021, DOI: 10.1039/D1CC01441B
J. Short, T. J.Blundell, S. Krivickas, S. Yang, J. D. Wallis, H. Akutsu, Y. Nakazawa and L. Martin, Chiral Molecular Conductor With An Insulator-Metal Transition Close To Room Temperature, Chem. Commun., 2020, 56, 9497–9500. DOI: 10.1039/D0CC04094K
J. Short, T. J. Blundell, S. Yang, O. Sahin, Y. Shakespeare, E. L. Smith, J. D. Wallis and L. Martin, Synthesis and Structures of Polyiodide Radical Cation Salts of Donors Combining Tetrathiafulvalene with Multiple Thiophene or Oligo-thiophene Substituents, CrystEngComm, 2020, 22, 6632-6644 DOI: 10.139/D0CE00954G
S. Imajo, H. Akutsu, A. Akutsu-Sato, A. L. Morritt, L. Martin and Y. Nakazawa, Effects of electron correlations and chemical pressures on superconductivity of β''-type organic compounds, Phys. Rev. Research 1, 033184 – Published 18 December 2019. DOI: https://doi.org/10.1103/PhysRevResearch.1.033184
A. L. Morritt, J. R. Lopez, T. J. Blundell, E. Canadell, H. Akutsu, Y. Nakazawa, S. Imajo and L. Martin, 2D Molecular Superconductor to Semiconductor Transition in the β”-(BEDT-TTF)2[(H2O)(NH4)2M(C2O4)3].18-crown-6 series (M = Rh, Cr, Ru, Ir), Inorganic Chemistry, 2019, 58, 10656-10664. DOI: 10.1021/acs.inorgchem.9b00292
L. Martin, Molecular conductors of BEDT-TTF with tris(oxalato) metallate anions, Coord. Chem. Rev., 2018, 376, 277-291. DOI:10.1016/j.ccr.2018.08.013
L. Martin, J. R. Lopez, H. Akutsu, Y. Nakazawa and S. Imajo, Bulk Kosterlitz-Thouless type molecular superconductor β”-(BEDT-TTF)2[(H2O)(NH4)2Cr(C2O4)3].18-crown-6, Inorganic Chemistry, 2017, 56(22), 14045-14052. DOI:10.1021/acs.inorgchem.7b02171
L. Martin, A. L. Morritt, J. R. Lopez, H. Akutsu, Y. Nakazawa, S. Imajo and Y. Ihara, Ambient-pressure molecular superconductor with a superlattice containing layers of tris(oxalato)rhodate enantiomers and 18-crown‑6, Inorganic Chemistry, 2017, 56 (2), 717-720. DOI: 10.1021/acs.inorgchem.6b02708
L. Martin, J. D.Wallis, M. Guziak, P. Maksymiw, F. Konalian-Kempf, A. Christian, S.-i. Nakatsuji, J.-i. Yamada and H. Akutsu, Enantiopure and racemic radical-cation salts of bis(2’-hydroxylpropylthio)(ethylenedithio)TTF with polyiodide anions, Dalton Transactions, 2017, 46, 4225-4234. DOI: 10.1039/C6DT04645B
L. Martin, A. L. Morritt, J. R. Lopez, Y. Nakazawa, H. Akutsu, S. Imajo, Y. Ihara, B. Zhang, Y. Zhang and Y. Guo, Molecular Conductors from bis(ethylenedithio)tetrathiafulvalene with tris(oxalato)rhodate, Dalton Transactions, 2017, 46, 9542-9548. DOI: 10.1039/C7DT00881C
J. R. Lopez, L. Martin, J. D. Wallis, H. Akutsu, J.-i. Yamada, S.-i. Nakatsuji, C. Wilson, J. Christensen and S. J. Coles, New semiconducting radical-cation salts of chiral bis(2-hydroxylpropylthio)ethylenedithioTTF, CrystEngComm, 2017, 19, 4848-4856. DOI: 10.1039/c7ce01014a