Bose glass in Ca₂RuO₄ nanofilms

NOBUKANE Hiroyoshi

Department of Physics

Sep. 18, 2026

膜厚を制御することで電子相関の強さが変化し、超伝導（SC)、ボースグラス（BG）、フェルミグラス（FG)、モット（Mott)絶縁体の各状態が現れる。ボースグラス相は約220Kまで広がり、高温で局在したクーパー対の存在を示唆する。

Press release (in Japanese)

Abstract
Weak localization of bosons can give rise to an exotic quantum state known as a Bose glass, characterized by the absence of global phase coherence yet finite conductivity. Here, we report signatures of a Bose glass state in the weak localization regime of the ruthenium oxide Ca₂RuO₄ nanofilms. The electrical resistivity exhibits a characteristic logarithmic temperature dependence, ρ ~ ln(1/T), consistent with bosonic weak localization. Furthermore, β-function scaling analysis reveals a distinct “vertical flow,” indicating a qualitative change in scaling behavior associated with localized bosonic transport. These results….

Read the original article on Communications Materials

Article inforamation
Hiroyoshi Nobukane, Koki Hirose, Kakeru Isono, Mizuki Higashiizumi, Masahito Sakoda, Korekiyo Takahashi & Satoshi Tanda, Bose glass in Ca₂RuO₄ nanofilms, Communications Materials, 7, 241 (2026)
DOI：10.1038/s43246-026-01325-4