摘要
Ferromagnetic quantum critical points were predicted to be prohibited in clean itinerant ferromagnetic systems,yet such a phenomenon was recently revealed in CeRh_(6)Ge_(4),where the Curie temperature can be continuously suppressed to zero under a moderate hydrostatic pressure.Here we report the observation of quantum oscillations in CeRh_(6)Ge_(4)from measurements using the cantilever and tunnel-diode oscillator methods in fields up to 45 T,clearly demonstrating that the ferromagnetic quantum criticality occurs in a clean system.In order to map the Fermi surface of CeRh_(6)Ge_(4),we performed angle-dependent measurements of quantum oscillations at ambient pressure,and compared the results to density functional theory calculations.The results are consistent with the Ce 4f electrons remaining localized and not contributing to the Fermi surface,suggesting that localized ferromagnetism is a key factor for the occurrence of a ferromagnetic quantum critical point in CeRh_(6)Ge_(4).
研究表明,反铁磁量子相变广泛存在于不同的关联电子材料体系中,但铁磁量子相变一直缺乏确凿的实验证据.理论预言,纯净的巡游铁磁体系中不存在铁磁量子临界点.最近,人们在重费米子化合物CeRh_(6)Ge_(4)中发现了压力诱导的铁磁量子临界点,并且观察到奇异金属行为.通过45 T强磁场条件下的机械悬臂磁矩测量和隧道二极管共振测量等实验方法,本文报道了CeRh_(6)Ge_(4)中的量子振荡,进一步证实该铁磁量子临界点出现在纯净的铁磁材料体系中.为了获取CeRh_(6)Ge_(4)的费米面,还测量了量子振荡随磁场转角的演化,并且将实验所得的量子振荡频率与密度泛函能带计算进行了对比,发现CeRh_(6)Ge_(4)中的4f电子呈现出局域化的特征,不对费米面产生贡献.这些结果表明,局域铁磁性是产生铁磁量子临界点的一个关键因素.
作者
An Wang
Feng Du
Yongjun Zhang
David Graf
Bin Shen
Ye Chen
Yang Liu
Michael Smidman
Chao Cao
Frank Steglich
Huiqiu Yuan
王安;杜锋;张勇军;David Graf;沈斌;陈晔;刘洋;Michael Smidman;曹超;Frank Steglich;袁辉球(Center for Correlated Matter and Department of Physics,Zhejiang University,Hangzhou 310058,China;Institute for Advanced Materials,Hubei Normal University,Huangshi 435002,China;National High Magnetic Field Laboratory and Department of Physics,Florida State University,Tallahassee,FL 32306,USA;Zhejiang Province Key Laboratory of Quantum Technology and Device,Department of Physics,Zhejiang University,Hangzhou 310058,China;Department of Physics,Hangzhou Normal University,Hangzhou 310036,China;Max Planck Institute for Chemical Physics of Solids,Dresden 01187,Germany;State Key Laboratory of Silicon Materials,Zhejiang University,Hangzhou 310058,China)
基金
the National Key R&D Program of China(2017YFA0303100,and 2016YFA0300202)
the National Natural Science Foundation of China(12034017,U1632275,and 11974306)
the Science Challenge Project of China(TZ2016004)
the Key R&D Program of Zhejiang Province(2021C01002)
supported by the National Science Foundation Cooperative Agreement No.DMR-1644779 and the State of Florida。
