Large spontaneous Hall effect arising from collinear antiferromagnetism in CePtGe

松田 駿汰*; 日比野 瑠央*; 田端 千紘; 金子 耕士   ; 比嘉 野乃花*; 鬼丸 孝博*; 田中 裕斗*; 藤 秀樹*; 菅原 仁*; 林 純一*; 武田 圭生*; 小手川 恒*

Matsuda, Hayata*; Hibino, Ruo*; Tabata, Chihiro; Kaneko, Koji; Higa, Nonoka*; Onimaru, Takahiro*; Tanaka, Hiroto*; To, Hideki*; Sugawara, Hitoshi*; Hayashi, Junichi*; Takeda, Keiki*; Kotegawa, Hisashi*

The spontaneous Hall effect, corresponding to a zero-field anomalous Hall effect (AHE), is induced by symmetry breaking associated with ferromagnetism. Studies in recent years, however, have revealed that antiferromagnetic (AFM) states characterized by magnetic point groups that allow ferromagnetism can also break the relevant symmetries and induce AHE without a large net magnetization. Here, we report that the AFM system CePtGe exhibits a pronounced spontaneous Hall effect. Single-crystal neutron scattering experiments demonstrate that CePtGe exhibits a collinear AFM structure with a propagation vector = 0. The small net magnetization indicates that the observed AHE arises from symmetry breaking inherent to its AFM structure. The anomalous Hall conductivity (AHC) reaches 300 cm, which exceeds the intrinsic AHC of related compounds such as CeCuGe and CePdGe. This large AHC, most likely attributed to the large spin-orbit coupling of the Pt atoms, provides a platform for understanding the interplay between the Berry curvatures and localized f-moments with an AFM configuration.