- Realization of phase transitions through modulation of electron–electron interactions in oxide heterostructures: Outcome of an international collaborative study

- Gaining attention as a core operating principle for next-generation AI semiconductor devices

  The research team led by Professor Young Jun CHANG of the Department of Physics at the University of Seoul, in collaboration with Dr. Eli Rotenberg of Lawrence Berkeley National Laboratory in the United States, successfully realized a Mott metal–insulator transition solely through the modulation of electron–electron interactions in lanthanum titanium oxide (LaTiO₃) heterostructure thin films. The research findings were published in the January 2026 issue of Communications Materials, a sister journal of Nature (Impact Factor: 9.6).

  This study is considered the first demonstration of a Mott transition induced solely by the precise control of on-site Coulomb interactions, achieved through the modulation of thin-film thickness and associated changes in charge transfer and lattice structure, rather than by external stimuli such as doping, temperature, or pressure. Using experimental techniques including angle-resolved photoemission spectroscopy and electron diffraction, together with first-principles calculations, the research team systematically analyzed the effects of monolayer-level thickness control on the electronic structure and phase-transition characteristics.

  Professor Young Jun CHANG stated, “The Mott transition observed in titanium oxide heterostructures represents a new approach to driving phase transitions by directly controlling electron–electron interactions (U), unlike conventional methods based on bandwidth control or doping,” adding that, “this provides a physical foundation for realizing the nonvolatile switching behavior essential for neuromorphic AI semiconductors that emulate neural circuits, and could serve as an important breakthrough in the development of next-generation artificial intelligence computing devices.”

▶ Dr. Byoung Ki CHOI (left, first author) and Professor Young Jun CHANG (right, corresponding author)

  This research was supported by the Mid-Career Researcher Support Program funded by the Ministry of Science and ICT and the National Research Foundation of Korea, as well as the Postdoctoral Overseas Training Program, the Overseas Large-Scale Research Facility Utilization Research Program (Advanced Quantum Material Synchrotron Research Center), the Group Research Support Program (Extreme Quantum Functional Material Research Center), and the reMIND program of the U.S. Department of Energy. This international collaborative study was made possible by the integration of the University of Seoul’s high-precision thin-film synthesis and spectroscopic analysis capabilities, the world-class synchrotron experimental infrastructure at Lawrence Berkeley National Laboratory, and the theoretical calculations and electronic-structure analysis expertise of Texas A&M University and KIST.