Part of the work of Dr Dai Aoki has been performed in collaboration with the IMAPEC lab of Pheliqs. He had been a postdoctoral researcher in CEA from 2000 – 2002 and a staff member from 2007 – 2013. Then he moved to the Institute for Materials Research of Tohoku University, but continued a strong and productive collaboration with Pheliqs in the field of unconventional superconductors. 

 The 4 papers cited as representative of Dai’s achievement in the field of unconventional superconductivity in actinide compounds are all involving the collaboration with IMAPEC, and the first two are from his work when he was in Grenoble:

• D. Aoki, A. Huxley, E. Ressouche, D. Braithwaite, J. Flouquet, J-P. Brison, E. Lhotel, C.Paulsen, “Coexistence of superconductivity and ferromagnetism in URhGe” Nature 413, 613 (2001).
• D. Braithwaite, D. Aoki, J-P. Brison, J. Flouquet, G. Knebel, Ai Nakamura, and A. Pourret, “Dimensionality Driven Enhancement of Ferromagnetic Superconductivity”. Phys. Rev. Lett. 120, 037001 (2018).
•  D. Aoki, A. Nakamura, F. Honda, D. Li, Y. Homma, Y. Shimizu, Y.J. Sato, G. Knebel, J.- P. Brison, A. Pourret, D. Braithwaite, G. Lapertot, Q. Niu, M. Valiska, H. Harima, J. Flouquet, “Unconventional superconductivity in heavy fermion UTe2” J. Phys. Soc. Jpn. 88, 043702 (2019).
•  D. Aoki, F. Honda, G. Knebel, D. Braithwaite, A. Nakamura, D. Li, Y. Homma, Y.Shimizu, Y.J. Sato, J.-P. Brison, J. Flouquet, “Multiple superconducting phases and unusual enhancement of the upper critical field in UTe2” J. Phys. Soc. Jpn. 89, 053705 (2020)

Research Summary
Superconductivity and ferromagnetism are among the most dramatic phase transition phenomena observed in materials and are positioned as central research topics in modern physics. These two phenomena have long been considered incompatible, like oil and water, and their coexistence was widely deemed impossible. 

 Professor Aoki discovered the actinide compound URhGe (uranium-rhodium-germanium) and demonstrated the microscopic coexistence of superconductivity and ferromagnetism even at ambient pressure. This discovery led to the identification of the “reentrant superconductivity” phenomenon, in which a superconducting phase, once lost under a magnetic field, reappears in a strong magnetic field. This breakthrough opened up a new research domain for “spin-triplet superconductivity,” a novel superconducting state with a symmetry distinct from conventional superconductors. 

 Professor Aoki has thus played a pioneering role in the emerging field of ferromagnetic superconductivity. Now, he is working together with the IMAPEC team on the unconventional superconductor UTe2 (uranium ditelluride).