JPS Outstanding Paper Award Recognizes PI Inoue’s Discovery of Chiral Soliton Lattice in a Heavy-Fermion Material
Professor Katsuya Inoue, Principal Investigator at WPI-SKCM², has received the 2025 Outstanding Paper Award of the Physical Society of Japan, JPS, for his co-authored paper reporting the first observation of chiral soliton lattice structures in a heavy-fermion material.
Established in 1996, this prestigious award honors researchers whose publications have made seminal contributions to the advancement of physics. The award recognizes outstanding papers published in one of JPS’s three English-language journals: Journal of the Physical Society of Japan, Progress of Theoretical and Experimental Physics, and JPS Conference Proceedings. Now in its 29th year, the award highlights works of enduring impact, such as Inoue’s 2017 paper, whose findings continue to influence the study of chiral magnetism.
“[Despite] established methodologies, designing inorganic chiral magnets remains challenging. We have succeeded for the first time in synthesizing a chiral magnet containing lanthanide ions and have clarified its chiral magnetic structure,” says Inoue.
The award-winning paper was co-authored by researchers from across Hiroshima University, and included collaborators from Saitama University, the National Institutes for Quantum and Radiological Science and Technology in Hyogo, and the Nagoya Institute of Technology.
About the Awarded Research
The chiral soliton lattice, CSL, is a spiral arrangement of atomic spins inside a crystal, which can be pictured as countless tiny magnetic compasses rotating along a single axis forming a helical pattern. This non-trivial magnetic order arises from the Dzyaloshinskii–Moriya interaction, a magnetic effect that dictates the relationship between neighboring spins.
The phenomenon of CSL was first predicted in high-energy particle physics, but has exciting implications for condensed matter physics, as it can be tuned to offer new material functionalities with potential applications in spintronics.
The first evidence of the CSL was discovered in the monoaxial chiral helimagnet CrNb₃S₆, a transition metal compound. Thus, the awarded paper sought to explore whether similar structures could exist in a fundamentally different material. They focused on heavy-fermion materials, which are of interest for displaying exotic quantum phenomena such as unconventional superconductivity, non-Fermi liquid behavior and quantum criticality.
“When incorporating elements from heavy-fermion systems, like lanthanide ions, it is theoretically conceivable that they may exhibit chiral magnetic structures distinct from those of chiral magnets containing conventional transition metal ions; however, no successful examples were known,” explains Inoue.
The team synthesized a heavy-fermion (f-electron) material, Yb(Ni₁₋ₓCuₓ)₃Al₉, a new monoaxial chiral helical magnet and rare-earth compound.
Using resonant X-ray scattering, the team observed the CSL in the material, revealing that: the direction of rotation of the helical spin structure is altered by the left- or right-handedness of the crystal; higher harmonic components of the propagation vectors increase with applied magnetic field; and some properties of the f-electron system differ from those of d-electron systems.
The chiral soliton lattice is a prime example of the cross-disciplinary, emergent knotted and chiral phenomena that WPI-SKCM² researchers seek to understand and harness in creating metamatter for a sustainable future.
About the Physical Society of Japan
JPS is the nation’s leading organization for physicists, covering all fields of physics and fostering scientific progress in Japan and internationally. With over 15,000 members, JPS serves as a scholarly hub comparable to and in reciprocal partnership with major international societies such as the American Physical Society, the Korean Physical Society, and the German Physical Society.
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