Unconventional normal and superconducting states in spinel oxide superconductor LiTi₂O₄ thin films

Unconventional superconducting states emerging from exotic quantum many-body interactions have attracted significant attention since the discovery of cuprate superconductors. In particular, the interplay between superconductivity and geometric frustration in systems such as intermetallic kagome compounds and transition-metal spinel oxides has become a central focus of contemporary condensed matter physics. Here, by combining in situ epitaxial thin-film growth via pulsed laser deposition with spectroscopic measurements, we uncover the exotic nature of both the normal and superconducting states in the spinel oxide superconductor LiTi₂O₄ under the influence of charge frustration. Our study showcases LiTi₂O₄ as a representative system in which strong electron–phonon coupling, electron correlations, and geometric frustration intertwine, opening a new avenue toward unconventional superconductivity.