Xitong Xu, Yonglai Liu, Ning Xi, Mingfang Shu, Haitian ZHAO, Jiajun Xie, Guoliang Wu, Hao Chen, Meng He, Pengzhi Chen, Ze Wang, Zhentao Wang, Chuanying Xi, Mi Tian, Hongwei Du, Jie Ma, Xi Chen, Wei Li, Zhe Qu
Abstract The discovery of spin supersolid and its giant magnetocaloric effect has opened a new arena in frustrated quantum magnets and cutting-edge cryogenics. The intermetallic EuCo 2 Al 9 (ECA), for the first time, extends this intriguing phase from Mott insulators to a highly conductive metal. In this work, we systematically study the electrical transport properties of ECA, where itinerant electrons serve as a sensitive probe of the spin supersolid state. We observe anomalies both in the temperature-dependent resistivity and in the field-dependent magnetoresistance and Hall signals, which are attributed to the response of electrons to the Eu 2+ spins and their fluctuations. Moreover, Shubnikov–de Haas quantum oscillations at high magnetic fields reveal pronounced band splitting in the spin-polarized state. Our results reveal an intimate correspondence between electrical transport and magnetic transitions in ECA, deepening the understanding of this metallic spin supersolid.