Ferromagnetic quasi-atomic electrons in two-dimensional electride
Seung Yong Lee, Jae‐Yeol Hwang, Jongho Park, Chandani N. Nandadasa, Younghak Kim, Joonho Bang, Kimoon Lee, Kyu Hyoung Lee, Yunwei Zhang, Yanming Ma, Hideo Hosono, Young Hee Lee, Seong‐Gon Kim, Sung Wng Kim, Sung Wng Kim, Sung Wng Kim
Abstract
Abstract An electride, a generalized form of cavity-trapped interstitial anionic electrons (IAEs) in a positively charged lattice framework, shows exotic properties according to the size and geometry of the cavities. Here, we report that the IAEs in layer structured [Gd 2 C] 2+ ·2e − electride behave as ferromagnetic elements in two-dimensional interlayer space and possess their own magnetic moments of ~0.52 μ B per quasi-atomic IAE, which facilitate the exchange interactions between interlayer gadolinium atoms across IAEs, inducing the ferromagnetism in [Gd 2 C] 2+ ·2e − electride. The substitution of paramagnetic chlorine atoms for IAEs proves the magnetic nature of quasi-atomic IAEs through a transition from ferromagnetic [Gd 2 C] 2+ ·2e − to antiferromagnetic Gd 2 CCl caused by attenuating interatomic exchange interactions, consistent with theoretical calculations. These results confirm that quasi-atomic IAEs act as ferromagnetic elements and trigger ferromagnetic spin alignments within the antiferromagnetic [Gd 2 C] 2+ lattice framework. These results present a broad opportunity to tailor intriguing ferromagnetism originating from quasi-atomic interstitial electrons in low-dimensional materials.