A unified theory of ferromagnetic quantum phase transitions in heavy fermion metals  

作　　者：Jiangfan Wang Yi-Feng Yang 

机构地区：[1]Beijing National Laboratory for Condensed Matter Physics,Institute of Physics,Chinese Academy of Science,Beijing 100190,China [2]School of Physical Sciences,University of Chinese Academy of Sciences,Beijing 100190,China [3]Songshan Lake Materials Laboratory,Dongguan 523808,China

出　　处：《Science China(Physics,Mechanics & Astronomy)》2022年第5期104-113,共10页中国科学：物理学、力学、天文学（英文版）

基　　金：supported by the National Key Research and Development Program of China(Grant No.2017YFA0303103);the National Natural Science Foundation of China(Grant Nos.12174429,and 11974397);the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB33010100)。

摘　　要：Motivated by the recent discovery of a continuous ferromagnetic quantum phase transition in Ce Rh_(6)Ge_(4) and its distinction from other U-based heavy fermion metals such as UGe_(2),we develop a unified explanation of their different ground state properties based on an anisotropic ferromagnetic Kondo-Heisenberg model.We employ an improved large-N Schwinger boson approach and predict a full phase diagram containing both a continuous ferromagnetic quantum phase transition for large magnetic anisotropy and first-order transitions for relatively small anisotropy.Our calculations reveal three different ferromagnetic phases including a half-metallic spin selective Kondo insulator with a constant magnetization.The Fermi surface topologies are found to change abruptly between different phases,consistent with that observed in UGe_(2).At finite temperatures,we predict the development of Kondo hybridization well above the ferromagnetic long-range order and its relocalization near the phase transition,in good agreement with band measurements in Ce Rh_(6)Ge_(4).Our results highlight the importance of magnetic anisotropy and provide a unified theory for understanding the ferromagnetic quantum phase transitions in heavy fermion metals.

关 键 词：ferromagnetic Kondo lattice magnetic anisotropy ferromagnetic quantum phase transition Schwinger boson 

分 类 号：O469[理学—凝聚态物理]