Visualization of spin–orbit-entangled 4f electrons in crystalline materials - Shunsuke Kitou; Kentaro Ueda; Yuiga Nakamura; Kunihisa Sugimoto; Yusuke Nomura; Ryotaro Arita; Yoshinori Tokura; Taka-hisa Arima (Proceedings of the National Academy of Sciences, 2025)