Magnetism of NaYbS_(2):From finite temperatures to ground state  

作　　者：Weizhen Zhuo Zheng Zhang Mingtai Xie Anmin Zhang Jianting Ji Feng Jin Qingming Zhang 

机构地区：[1]School of Physical Science and Technology,Lanzhou University,Lanzhou 730000,China [2]Beijing National Laboratory for Condensed Matter Physics,Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China

出　　处：《Science China(Physics,Mechanics & Astronomy)》2024年第10期92-104,共13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.2022YFA1402704);the National Science Foundation of China(Grant No.12274186);the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB33010100);the Synergetic Extreme Condition User Facility(SECUF)。

摘　　要：Rare-earth chalcogenide compounds ARECh_(2)(A=alkali or monovalent metal,RE=rare earth,Ch=O,S,Se,Te)are a large family of quantum spin liquid(QSL)candidate materials.NaYbS2is a representative member of the family.Several key issues on NaYbS_(2),particularly how to determine the highly anisotropic spin Hamiltonian and describe the magnetism at finite temperatures and the ground state,remain to be addressed.In this paper,we conducted an in-depth and comprehensive study on the magnetism of NaYbS_(2) from finite temperatures to the ground state.Firstly,we successfully detected three crystalline electric field(CEF)excitation energy levels using low-temperature Raman scattering technique.Combining them with the CEF theory and magnetization data,we worked out the CEF parameters,CEF energy levels,and CEF wavefunctions.We further determined a characteristic temperature of~40 K,above which the magnetism is dominated by CEF excitations while below which the spinexchange interactions play a main role.The characteristic temperature has been confirmed by the temperature-dependent electron spin resonance(ESR)linewidth.Low-temperature ESR experiments on the dilute magnetic doped crystal of NaYb_(0.1)Lu_(0.9)S_(2) further helped us to determine the accurate g-factor.Next,we quantitatively obtained the spin-exchange interactions in the spin Hamiltonian by consistently simulating the magnetization and specific heat data.Finally,the above studies allow us to explore the ground state magnetism of NaYbS_(2) by using the density matrix renormalization group.We combined numerical calculations and experimental results to demonstrate that the ground state of NaYbS_(2) is a Dirac-like QSL.

关 键 词：rare-earth chalcogenide anisotropic spin Hamiltonian quantum spin liquid 

分 类 号：O469[理学—凝聚态物理]