DATE2025.12.11 #Press Releases

Emergence of Superconductivity by Suppressing Crystal Distortion

-Property Control via Integer-Ratio Lattice Matching at Thin-Film Interfaces-

Summary

A joint research team consisting of Yuki Sato, Special Postdoctoral Researcher, and Minoru Kawamura, Team Leader, of the RIKEN Center for Emergent Matter Science (CEMS) Topological Electronics Research Team; Yoshinori Tokura, Team Leader of the Strong Correlation Quantum Transport Research Team (Distinguished Professor, The University of Tokyo / Tokyo College, UTIAS); Ryotaro Arita, Team Director of the Computational Materials Science Research Team (Professor, Graduate School of Science, The University of Tokyo); Soma Nagahama, doctoral student, and Professor Atsushi Tsukazaki of the Graduate School of Engineering, The University of Tokyo; and Associate Professor Hajime Sagayama of the Institute of Materials Structure Science, KEK, has demonstrated a method to effectively suppress the intrinsic low-temperature crystal distortion in thin-film samples and thereby induce superconductivity.

This achievement proposes a new approach for externally controlling material properties and is expected to enable further applications across various materials in fields such as semiconductor engineering and superconducting electrical circuits.

In thin-film materials research, materials are typically designed so that one lattice unit of the film grows on one lattice unit of the substrate, enabling the synthesis of high-quality crystalline films. In contrast to this conventional guideline, the present study discovered that six lattice units of an FeTe thin film grow precisely on five lattice units of a CdTe substrate. This represents a special type of lattice matching—commensurate lattice matching—where the lattice constants of the two materials satisfy an integer-ratio relationship.

Such integer-ratio lattice matching normally leads to the formation of misfit dislocations (regions where the crystals of the substrate and film do not align), which has been considered detrimental to crystal quality. However, by conducting X-ray diffraction measurements to examine the thin-film crystal structure in detail down to low temperatures, the team found that the intrinsic crystal distortion that FeTe exhibits at low temperature is significantly suppressed in these commensurately matched films. Moreover, the distortion-suppressed thin films were discovered to exhibit superconductivity at low temperatures.

The results of this study were published online in Nature Communications on December 5.

Figure：Emergence of superconductivity in thin films with integer-ratio lattice matching and suppressed strain

Links

RIKEN, Graduate School of Engineering, The University of Tokyo, TOKYO COLLEGE, High Energy Accelerator Research Organization (KEK)

Journals

Journal name	Nature Communications
Title of paper	Superconductivity and suppressed monoclinic distortion in FeTe films enabled by higher-order epitaxy